Chapter : 14) S-block elements (Alkali and Alkaline earth metals)

Transcription

1 Chapter : 14) S-block elements (Alkali and Alkaline earth metals) Question ID: 1657 Q 1.Alkali metals are characterized by (A) good conductivity (B) high oxidation potentials (C) high melting point (D) solubility in liquid ammonia A. A and B B. B, C and D C. A, B and D D. All of these No Explanation Question ID: 1658 Q 2.In contrast to potassium, sodium has : A. Less electronegativity B. Lower ionization enthalpy C. lower m.p D. higher density Correct Option: D No Explanation

2 Question ID: 1659 Q 3.The salt added to table salt to make it flow freely in rainy season is A. KCl B. NH 4 Cl C. Ca 3 (PO 4 ) 2 D. MgCl 2 is used for this purpose as its prevents the absorption of water. Question ID: 1660 Q 4.Which among the following compounds is are paramagnetic? A. KO 2 B. K 2 O C. K 2 O 2 D. Both (1) and (3) Superoxides contain unpaired electron and is paramagnetic. Question ID: 1661 Q 5.Which of the following is not the correct use of caustic soda? A. For mercerizing cotton fabrics B. In the manufacture of artificial silk (rayon) C. In refrigeration D. To prepare soda lime

3 Caustic soda, also called sodium hydroxide is a very strong base. It is called caustic soda because of its corrosive (or irritating) effect on the skin. Actually it breaks down the proteins present in the skin. Question ID: 1662 Q 6.Which of the following minerals contain both Mg and Ca? A. Dolomite B. Tale C. Epsomite D. Anhydrite Dolomite is Talc is Magnesite is Anhydrite is Question ID: 1663 Q 7.A metal M readily forms water soluble sulphate MSO 4, water insoluble hydroxide M(OH) 2 and oxide MO which becomes inert on heating. The hydroxide is soluble in NaOH.M is A. Be B. Mg C. Ca D. Sr

4 Metal is Be and not Mg because being amphoteric soluble in NaOH but not. Question ID: 1664 Q 8.Potassium metal is commercially prepared by the reduction of molten KCl with metallic sodium at 850 C (1123 K). This method is based upon the principle that A. Sodium is more reactive than potassium at this temperature B. Potassium being more volatile distils off thus shifting the reaction forward C. Sodium prefers to bind to chloride ions in preference to potassium ions D. Potassium and sodium form an alloy at this temperature. Na prefers to bind to ion in preference to K Question ID: 1665 Q 9.A metal is present in plants, bones, egg shells and sea shells. It is also used to remove oxygen from molten steel. The metal is A. Al B. Ca C. Mg D. Na Correct Option: B

5 Calcium is used as scavanger of oxygen from molten steel. Question ID: 1666 Q 10.Which of the following is incorrect? A. Mg burns in air releasing dazzling light rich in U.V rays B. CaCl 2.6H 2 O when mixed with ice gives freezing mixture C. Mg cannot form complexes D. Be can form complexes due to its very small size Mg is present in the complex like chlorophyll. Question ID: 1667 Q 11.Which one of the following is the correct order for the decomposition temperature of CaCO 3 (x), MgCO 3 (y) and BaCO 3 (z)? A. z > x > y B. x > y > z C. y > z > x D. x > z > y Thermal stability of alkaline earth metal carbonates increase down the group. Thus, the order is

6 Question ID: 1668 Q 12.Gypsum on heating to 200 o C gives A. CaSO 4. 2H 2 O B. plaster of Paris C. dead burnt plaster D. quick lime and SO 3 Question ID: 1669 Q 13.An amphoteric oxide dissolves in HCl to form a salt. The salt does not impart any colour to the flame and fumes in moist air. The oxide is A. BaO 2 B. MgO C. BeO D. CaO No Explanation

7 Question ID: 1670 Q 14.KO 2 is used in space craft and submarines because it A. absorbs CO 2 and increases O 2 concentration B. absorbs moisture C. absorbs CO 2 D. produces ozone acts as a source of and removes. Question ID: 1671 Q 15.Molecular formula of Glauber's salt is: A. Na 2 SO 4. 10H 2 O B. FeSO 4. 7 H 2 O C. CuSO 4. 5H 2 O D. MgSO 4. 7H 2 O Glauber's salt is Question ID: 1672 Q 16.Mixture of MgCl 2 and MgO is called : A. Portland cement B. Sorrel's cement C. double salt D. none of these

8 Correct Option: B Sorrels cement is Question ID: 1673 Q 17.Estimation of calcium and magnesium is done by : A. EDTA B. oxalate C. phosphate D. none of these EDTA forms a complex with and ions. Question ID: 1674 Q 18.In the presence of cobalt chloride, bleaching powder decomposes to form A. CaCO 3 and O 3 B. ClO 2 and CaO C. Cl 2 O and CaO D. CaCl 2 and O 2 Correct Option: D

9 Question ID: 1675 Q 19.Which one of the following is dead burnt plaster? A. B. C. D. Anhydrous Correct Option: D Anhyd. is known as dead burnt plaster. Question ID: 1676 Q 20.The alkaline earth metal harder than glass is A. Be B. Mg C. Ca D. none of these Beryllium is harder than glass.

10 Question ID: 1677 Q 21.The ignition mixture used in alumino thermy is a mixture of A. Mg powder + Na 2 O 2 B. Al powder + BaO 2 C. Al powder + Na 2 O 2 D. Mg powder + BaO 2 Correct Option: D No Explanation Question ID: 1678 Q 22.The hydration enthalpy of ions is higher than that of : A. B. C. D. none of these has smaller size than and thus has higher hydration enthalpy than. Question ID: 1679 Q 23.Francium was discovered by A. Perey

11 B. Davy C. Arfwedsen D. Bunsen The elements of groups 1 and 2 are known as s-block elements as the last electron in these enters the valence s- subshell. The elements of group 1 are : Li-Lithium Na- Sodium K-Potassium Rb - Rubidium Cs - Caesium Fr - Francium Lithium was discovered by Arfwedson (1817): Sodium and potassium by Davy (1807): rubidium and caesium by Bunsen (in 1861 and 1860 respectively). and francium by Perey (1939) Due to high chemical reactivity these do not occur free in the nature (native state). General electronic configuration of alkali metals is : [Noble gas ] and of alkaline earth metals is : [Noble gas ] Alkali metals are so named because they dissolve in water to form soluble hydroxides called alkalies. Group 2 elements are known as alkaline earth metals as their oxides are alkaline and occur in earth crust. Question ID: 1680 Q 24.What properties are explained by the presence of single electron in the valence shell of alkali metals? (I) Low ionization enthalpy (II) Low melting point (III) Weak metallic bond A. I only B. I, II C. I, III D. I, II, III Correct Option: D No Explanation

12 Question ID: 1681 Q 25.Which of the following has the least anion to cation size ratio? A. LiF B. NaF C. CsI D. CsF Correct Option: D ion has the smallest size and ion has the maximum size. Question ID: 1682 Q 26.Which of the following is least thermally stable? A. Li 2 CO 3 B. Na 2 CO 3 C. K 2 CO 3 D. Rb 2 CO 3 is least thermally stable because small sized cannot make carbonate lattice. Question ID: 1683 Q 27. ion imparts violet colour to the flame. This is due to the fact that the emitted radiations have : A. high energy B. low energy

13 C. longer wavelength D. none of three ion emits radiations of high energy. Question ID: 1684 Q 28.Alkali metals have high negative reduction potential. Hence they behave as: A. oxidising agents B. Lewis bases C. reducing agents D. electrolytes Alkali metals behave as reducing agents. Question ID: 1685 Q 29.Alkali metals impart colour to Bunsen flame due to A. low ionization energies B. low melting points C. their softness D. the presence of one electron in the outer most shell

14 No Explanation Question ID: 1686 Q 30.The strongest reducing agent out of Na, K, Rb and Cs is A. Na B. Cs C. Rb D. K Correct Option: B All alkali metals are strong reducing agents i.e. they can readily lose their valence electrons. This is due to low ionisation energy. The reducing nature increases down the group as ionisation energy decreases down the group from Na to Cs but exceptionally Li is the strongest reducing agent. This is due to its highest negative electrode potential value Question ID: 1687 Q 31.What will be the order of first ionization enthalpy? A. Li > Na > K B. K > Li > Na C. Na > Li > K D. Li > K > Na Down the group, size increases so I.E. decreases.

15 Question ID: 1688 Q 32.Which of the following alkali metals is most metallic in nature? A. Li B. Na C. K D. Rb Correct Option: D Down the group, metallic nature increases because I.E. decreases down the group. Question ID: 1689 Q 33.An important ore of magnesium is A. Malachite B. Cassiterite C. Carnallite D. Galena Carnallite is Malachite is Cassiterate is. It is an ore of Sn. Galena is PbS. It is an ore of Pb.. It is an ore of Mg.. It is an ore of Cu.

16 Question ID: 1690 Q 34.The formula of calcium cyanamide is A. Ca (CN) 2 B. CaC 2 N C. CaNCN D. CaCHNH 2 Calcium cynamide is Question ID: 1691 Q 35.The solubilities of sulphates of alkaline earth metals decrease from Be to Ba because A. hydration energies of cations decrease in this order B. their lattice energies decrease in this order C. their lattice energies increase in this order D. interionic attraction decreases Hydration enthalpy decreases from to due to increase in the size of cations down the group. Question ID: 1692 Q 36.A piece of magnesium ribbon was heated to redness in an atmosphere of nitrogen and on cooling, water was added, the gas evolved is A. hydrogen B. oxygen C. nitrogen

17 D. ammonia Correct Option: D Question ID: 1693 Q 37.Which of the following metals is kept wrapped in paraffin wax? A. Li B. Na C. Mg D. K No Explanation Question ID: 1694 Q 38.The following question contains two statements. Choose one of the options below: Statement 1 : The superoxides of alkali metals are paramagnetic and coloured. Statement 2 : The superoxide ion has one unpaired electron in one of the antibonding molecular orbitals. A. Statement-1 is True, Statement -2 is true, Statement - 2 is a correct explanation for Statement -1 B. Statement -1 is True, Statement -2 is true, Statement-2 is not a correct explanation for Statement-1 C. Statement-1 is True, Statement-2 is False D. Statement-1 is False, Statement-2 is True

18 Statement-1 and 2 both are true and statement-2 is a correct explanation for statement-1. Question ID: 1695 Q 39.The following question contains two statements. Choose one of the options below: Statement 1 : Addition of gypsum to cement slows down its rate of setting. Statement 2 : Gypsum converts tricalcium aluminate to calcium sulpho aluminate. A. Statement-1 is True, Statement -2 is true, Statement - 2 is a correct explanation for Statement -1 B. Statement -1 is True, Statement -2 is true, Statement-2 is not a correct explanation for Statement-1 C. Statement-1 is True, Statement-2 is False D. Statement-1 is False, Statement-2 is True Statement-1 and 2 both are true and statement-2 is a correct explanation for statement-1. Question ID: 1696 Q 40.The following question contains two statements. Choose one of the options below: Statement 1: The alkali metals can form ionic hydrides which contain the hydride ion Statement 2 : The alkali metals have low electronegativity. Their hydrides conduct electricity when fused and liberate hydrogen at the anode. A. Statement-1 is True, Statement -2 is true, Statement - 2 is a correct explanation for Statement -1 B. Statement -1 is True, Statement -2 is true, Statement-2 is not a correct explanation for Statement-1 C. Statement-1 is True, Statement-2 is False D. Statement-1 is False, Statement-2 is True Statement-1 and 2 both are true and statement-2 is a correct explanation for statement-1.

19 Question ID: 5052 Q 41.In certain respects, lithium differs from other alkali metals. The main reason for this is A. small size of lithium atom and ion B. extremely high electropositivity of Li C. greater hardness of Li D. unique electronic configuration Anomalous behaviour of Li is due to its smallest size. Question ID: 5053 Q 42.Nitrate of which of the following elements are converted to their oxides on heating? A. Li B. Na C. K D. Mg Correct Option: D Question ID: 5054 Q 43.Which of the following metals form stable carbonates? A. Na B. Li C. Mg D. none of these

20 is stable to heat. Question ID: 5055 Q 44.Photoelectric effect is maximum in A. Li B. Na C. K D. Cs Correct Option: D Cs shows maximum photoelectric effect due to lowest ionization enthalpy. Question ID: 5056 Q 45.Which of the following has the biggest radius? A. B. C. D.

21 has biggest radius as ionic radius increases down the group. Question ID: 5057 Q 46.When sodium heated in dry ammonia, the compound formed is : A. sodium amide B. sodium azide C. sodium nitride D. sodium hydride (sodium amide) is formed. Question ID: 5058 Q 47.Solution of sodium metal in liquid ammonia is strongly reducing due to the presence of in the solution A. sodium hydride B. sodium amide C. sodium atoms D. solvated electrons Correct Option: D Solvated electrons are responsible for reducing nature.

22 Question ID: 5059 Q 48.Excess of ions in our system cause A. High B.P B. Low B.P C. Diabetes D. Anaemia Excess of ions increases the osmotic pressure of blood. Question ID: 5060 Q 49.Prefix 'alkali' for alkali metals signifies: A. silvery luster B. metal nature C. ashes of plants D. active nature The word alkali is derived from Arabic word alkies meaning plant ashes since ashes are rich in (90%) Question ID: 5061 Q 50. A. B.

23 C. D. CO Correct Option: B Question ID: 5062 Q 51.Which of the following is not an ore of magnesium? A. Epsom salt B. Magnesite C. Calamine D. Sea water No Explanation Question ID: 5063 Q 52.Among the alkali metals cesium is the most reactive metal because A. its incomplete shell is nearest to the nucleus B. it has a single electron in the valence shell C. it is the heaviest alkali metal D. the outermost electron is more loosely bound than the outermost electron of the other alkali metals Correct Option: D

24 No Explanation Question ID: 5064 Q 53.Mg burns in A. N 2 B. CO 2 C. SO 2 D. All the three Correct Option: D Question ID: 5065 Q 54.Alkali metals have high oxidation potential and hence they behave is: A. oxidising agents B. lewis bases C. reducing agents D. electrolyte

25 No Explanation Question ID: 5066 Q 55.When washing soda is heated A. CO is released B. CO + CO 2 is released C. CO 2 is released D. water vapours are released Correct Option: D Question ID: 5067 Q 56.Lithium is the strongest reducing agent among the alkali metals due to which of the following factor A. ionization enthalpy B. electron affinity C. hydration enthalpy D. lattice enthalpy Due to greater hydration enthalpy, reduction potential of lithium is lowest and it is the strongest reducing agent.

26 Question ID: 5068 Q 57.Which sulphate has the highest solubility in water? A. BaSO 4 B. CaSO 4 C. BeSO 4 D. MgSO 4 has the highest solubility due to highest hydration energy in the group. Question ID: 5069 Q 58.Ba, Sr, Ca and Mg may be arranged in order of decreasing first ionization enthalpy (IE1) as: A. Mg, Ca, Sr, Ba B. Ca, Sr, Ba, Mg C. Sr, Ba, Mg, Ca D. Ba, Mg, Ca, Sr Due to increasing size, ionization enthalpy decreases down the group. Question ID: 5070 Q 59.On dissolving moderate amount of sodium metal in liquid ammonia at low temperature, which one of the following does not occur? A. Blue coloured solution is obtained B. ions are formed in solution C. Liquid NH 3 becomes good conductor of electricity

27 D. Liquid NH 3 remains diamagnetic Correct Option: D The solution becomes paramagnetic due to unpaired ammoniated electron. Question ID: 5071 Q 60.Which of the following is false? A. Na and K are soft metals and can be cut with a knife B. Na and K have lesser density than water C. Na and K burn in air to give peroxides D. Na and K are stored in kerosene oil to avoid reaction with air and water No forms peroxides but K forms superoxides. Question ID: 5072 Q 61.Which of the following statements is not true for lithium? A. It is the hardest alkali metal B. It reacts with nitrogen forming Li 3 N C. Lithium is the strongest reducing agent D. Lithium forms ionic compounds Correct Option: D

28 Lithium forms covalent compounds. Question ID: 5073 Q 62.Which of the following is used as a source of O 2 in space capsules, submarines etc? A. K 2 O B. Na 2 O 2 C. Li 2 O D. Na 2 O Correct Option: B is used as a source of oxygen in space capsules and submarines. Question ID: 5074 Q 63.Sodium metal is and than potassium? A. Lighter, more reactive B. Heavier, less reactive C. Lighter, less reactive D. Heavier, more reactive Correct Option: B Sodium is heavier (more denser) and less reactive than potassium.

29 Question ID: 5075 Q 64.Steam is passed through the tank in Nelson's cell. Its function is to A. to keep the electrolyte warm B. to keep the pores of U-tube open C. both are correct D. none of the two is correct No Explanation Question ID: 5076 Q 65.In the manufacture of NaOH by electrolysis of an aqueous solution of sodium chloride, the cathode and anode are separated by using a diaphragm or slate partitions because A. It prevents the reaction between NaOH and Cl 2 B. It increases the yield of products C. It prevents the mixing of NaCl and NaOH D. It prevents the reaction between Na and Cl 2 Diaphragm or slate partitions are used to prevent the (evolved at anode) from coming in contact with NaOH solution which otherwise will form NaCl and sodium hypochlorite. Question ID: 5077 Q 66.What will happen when standard solution of NaOH is left in air for few hours? A. A precipitate will be formed

30 B. The strength of the solution will increase C. The strength of the solution will decrease D. The concentration of ions will remain same The strength of NaOH solution will decrease because NaOH is hygroscopic and absorbs moisture from air. Question ID: 5078 Q 67.A metal X on heating in nitrogen gas gives Y. Y on treatment with H 2 O gives a colourless gas which when passed through CuSO 4 solution gives a blue colour. Y is A. Mg (NO 3 ) 2 B. Mg 3 N 2 C. NH 3 D. MgO Correct Option: B Compound Y is which involves with water. The gas gives a blue colour with solution. Question ID: 5079 Q 68.Which of the following hydrated salts will give anhydrous salt on heating? A. MgCl 2.6H 2 O

31 B. CaCl 2. 6 H 2 O C. AlCl 3. 6H 2 O D. SnCl 2. 2H 2 O Correct Option: B Only (2) give anhydrous salt on heating. (1) gets decomposed on heating. (3) gets decomposed on heating. (4) undergoes hydrolysis on heating. Question ID: 5080 Q 69.A colourless solid (A) on heating evolve CO 2 and give a white residue (B) soluble in water. (B) also give CO 2 when treated with dilute acid. (A) is A. Na 2 CO 3 B. NaHCO 3 C. CaCO 3 D. Ca(HCO 3 ) 2 Correct Option: B

32 Question ID: 5081 Q 70.Li 2 CO 3 + Na 2 CO H 2 O mixture is heated to give residue. The loss in weight is due to A. Loss of water only B. Loss of CO 2 only C. Both D. None Question ID: 5082 Q 71.Presence of which of the following salt increases the rate of setting of plaster of paris A. KCl B. NaCl C. BaSO 4 D. CuSO 4 Correct Option: B NaCl increases the rate of setting of plaster of paris whereas alum or borax retards it. Question ID: 5083 Q 72.Sodium sulphate is soluble in water whereas barium sulphate is sparingly soluble because: A. The hydration energy of sodium sulphate is more than its lattice energy

33 B. The lattice energy of barium sulphate is less than its hydration energy C. The lattice energy has no role to play in solubility D. The hydration energy of sodium sulphate is less than its lattice energy When H.E. > L. E. the salt is soluble in water. Question ID: 5084 Q 73.Highly pure dilute solution of sodium in liquid ammonia (A) shows blue colour (B) exhibits electrical conductivity (C) produces sodium amide (D) produces hydrogen gas A. A and B B. A, B and C C. B, C and D D. All of these are correct Highly pure dilute solution of sodium in liquid ammonia is blue in colour due to ammoniated electron. This solution is conducting due to both ammoniated cation and ammoniated electron. Question ID: 5085 Q 74.The correct order of the mobility of the alkali metal ions in aqueous solution is A. B.

34 C. D. Smaller the size of ion, more is its hydration and thus lesser is its monthly. Down the group, size of ions increase and size of hydrated ions decrease. Thus monthly increases down the group of alkali metal. Question ID: 5086 Q 75.Which one of the following materials is used in high temperature thermometers? A. crystalline sodium chloride B. molten aluminium C. sodium smalgam D. alloy of sodium and potassium Correct Option: D No Explanation Question ID: 5087 Q 76.Which one of the following alkali metals emits light of longest wavelength in flame test? A. Li B. Na C. K D. Cs

35 Due to its small size. Question ID: 5088 Q 77.A fire of lithium, sodium and potassium can be extinguished by : A. H 2 O B. Nitrogen C. CO 2 D. Asbestos blanket Alkalimetal fire cannot be extinguished with water. It is extinguished with based fire extinguishers. Question ID: 5089 Q 78.On strong heating sodium bicarbonate changes into: A. sodium monoxide B. sodium hydroxide C. sodium carbonate D. sodium peroxide No Explanation

36 Question ID: 5090 Q 79.Which of the following is not an ore of magnesium? A. Carnallite B. Magnesite C. Dolomite D. Gypsum Correct Option: D Gypsum is Question ID: 5091 Q 80.Aluminium reacts with caustic soda to form A. aluminium hydroxide B. aluminium oxide C. sodium meta aluminate D. sodium tetra aluminate Question ID: 5092 Q 81.The composition of the common glass is : A. Na 2 O. CaO. 6SiO 3 B. Na 2 O. Al 2 O 3. SiO 2

37 C. CaO. Al 2 O 3. SiO 2 D. Na 2 O. CaO. 6 SiO 2 Correct Option: D No Explanation Question ID: 5093 Q 82.Since at freshly cut sodium is A. due to oscillation of free electrons B. due to weak metallic bonding C. due to absorption of light in crystal lattice D. due to presence of free valency at the surface No Explanation Question ID: 5094 Q 83.The difference of water molecules in gypsum and plaster of paris is: A. B. 2 C. D. Correct Option: D

38 Gypsum : Plaster of Paris : Question ID: 5095 Q 84.When CO 2 is passed through solution of calcium hydroxide, which one of the following compound is precipitated? A. Ca (HCO 3 ) 2 B. CaO C. CaCO 3 D. Ca (OH) 2 Question ID: 5096 Q 85.Which is the correct order of increasing basic strength? A. MgO < BeO < CaO < BaO B. BeO < MgO < CaO < BaO C. BaO < CaO < MgO < BeO D. CaO < BaO < BeO < MgO Correct Option: B

39 Basic character of oxides decreases down the group. Question ID: 5097 Q 86.Which of the following is present in chlorophyll? A. Mg B. Be C. Ca D. None of these No Explanation Question ID: 5098 Q 87.All the following substances react with water. The pair which gives the same gaseous product is : A. K and KO 2 B. Na and Na 2 O 2 C. Ca and CaH 2 D. Ba and BaO 2 Ca and give the same product.

40 Question ID: 5099 Q 88.To clear solution of compound (X), a solution of barium chloride (BaCl 2 ) is added to give a white precipitate which does not dissolve in dilute HCl. The compound (X) is : A. a nitrate B. a bromide C. a sulphate D. a carbonat X is sulphate because is insoluble in dil. HCl. Question ID: 5100 Q 89.Which of the following metal ions plays an important role in muscle contraction? A. B. C. D. Correct Option: D ions are involved in muscle contraction. Question ID: 5101 Q 90.which constitutes the enamel of our teeth?

41 A. Ca 3 (PO 4 ) 2. CaF 2 B. CaF 2 C. CaCO 3 D. CaSO 4. 2H 2 O constitutes the enamel of our teeth. Question ID: 5102 Q 91.A metal is burnt in air and the ash on moistening gives smell of ammonia. The metal is A. Na B. Fe C. Mg D. Al Mg burns in air to form which is decomposed by water to evolve gas. Question ID: 5103 Q 92.The hydroxide which is most soluble in water is? A. Ba (OH) 2 B. Mg (OH) 2 C. Sr (OH) 2 D. Ca(OH) 2

42 The solubility of hydroxides of alkaline earth metals increases down the group due to decrease in lattice energy. Question ID: 5104 Q 93.A chloride dissolves appreciably in cold water. When placed on the tip of platinum wire and heated in Bunsen flame, no distinctive colour is obtained. Which cation could be present? A. B. C. D. Beryllium salts do not impart colour to the flame. Question ID: 5105 Q 94.Chemical compound 'A' is used to remove temporary hardness from water. It reacts with Na 2 CO 3 to generate caustic soda. When CO 2 is bubbled through 'A', it turns cloudy. What is the chemical formula of 'A'? A. CaCO 3 B. CaO C. Ca(OH) 2 D. Ca(HCO 3 ) 2

43 No Explanation Question ID: 5106 Q 95.Which of the following elements forms predominantly covalent bonds? A. Ba B. Sr C. Ca D. Be Correct Option: D The compounds of Be are mostly covalent in nature. Question ID: 5107 Q 96.Which alkali metals does not form super oxides? A. Na only B. Li only C. Rb only D. Both (1) and (2) Correct Option: D No Explanation

44 Question ID: 5108 Q 97.The ions having highest ionic mobility in aqueous solution is A. B. C. D. Correct Option: D This is because (due to greater size) is least hydrated and hydrated ion being smaller moves rapidly. Question ID: 5109 Q 98.Which of the following is used as Barium meal for taking the X-ray of digestive system? A. CaSO 4 B. BaSO 4 C. MgSO 4 D. CaCO 3 Correct Option: B is used since it does not ionise. Question ID: 5110 Q 99.Anhydrous MgCl 2 can be prepared by heating MgCl 2. 6 H 2 O : A. with coke

45 B. with lime C. in a current of dry HCl D. directly Direct heating cannot be done as it would cause hydrolysis. Question ID: 5111 Q 100.Polymerization of isoprene into synthetic rubber is catalyzed by A. Li B. Na C. K D. all the three Correct Option: B No Explanation Question ID: 5112 Q 101.As compared to NaHCO 3, the solubility of KHCO 3 in water is A. More B. less C. equal D. none of the above

46 No Explanation Question ID: 5113 Q 102.MgBr 2 is soluble in acetone because of A. polar nature B. covalent nature C. ionic nature D. high lattice energy Correct Option: B has covalent character, so it is soluble in acetone. Question ID: 5114 Q 103.On moving down the group, the reducing power of alkaline earth metals A. decreases B. increases C. remain unchanged D. first increases and then decreases Down the group, ionisation energy decreases so tendency to lose electron and hence reducing power increases.

47 Question ID: 5115 Q 104.A substance which gives a brick red flame and breaks down on heating to give oxygen and a brown gas is A. magnesium nitrate B. calcium carbonate C. calcium nitrate D. magnesium carbonate Correct Option: D Question ID: 5116 Q 105.The density of Ca is less than that of Mg because A. nuclear charge of Ca is more than Mg B. vacant 3d orbital is present in Ca C. size of Ca is less than Mg D. none of the above Correct Option: B Due to the presence of vacant d-orbitals, atomic volume increase largely which results in the decrease of density in Ca. Question ID: 5117 Q 106.Which of the following is used as a scavenger in metallurgy?

48 A. Na B. K C. Ca D. Zn Calcium is used as a scavenger of oxygen and nitrogen in metallurgical operation. Question ID: 5118 Q 107.Which of the following is not a use of Epsom salt? A. As a purgative B. As a mordant in dyeing C. As a stimulant to increase the secretion of bile D. For removal of sulphur from petroleum Correct Option: B No Explanation Question ID: 5119 Q 108.Gypsum is added to clinker during cement manufacture to A. decrease the rate of setting of cement B. bind the particles of calcium silicate C. provide CaO D. carry away the heat

49 Gypsum is added to decrease the rate of setting of cement and it converts fast setting tricalcium aluminate to calcium sulphoaluminate which sets slowly. Question ID: 5120 Q 109.Flash bulbs contain a foil of magnesium packed in the atmosphere of A. Nitrogen B. Air C. Halogens D. SO 2 Inert atmosphere is provided by nitrogen. Question ID: 5121 Q 110.The alloy electron used in the construction of air crafts has the composition A. 15% Mg, 85% Al B. 95% Mg, 5% Zn C. 95% Mg, 5% Al D. 80% Mg, 20% Zn Correct Option: B

50 No Explanation Question ID: 5122 Q 111.The apparatus used to measure and ion level in body fluids is known as A. Dialyser B. Flame photometer C. Agoniometer D. Potentiometer Correct Option: B No Explanation Question ID: 5123 Q 112.When excess of Na 2 S 2 O 3 is added to dil. AgNO 3, a soluble compound 'X' is formed. However, when dil. Na 2 S 2 O 3 is added to conc. AgNO 3 solution, a white precipitate, turning yellow and finally black precipitate of 'Y; is formed. Which is correct pair? A. X is Ag 2 S and Y is Na 3 [Ag(S 2 O 3 ) 2 ] B. X is Na 3 [Ag(S 2 O 3 ) 2 ] and Y is Ag 2 S C. X is Ag 2 S 2 O 3 and Y is Ag 2 S D. X is Ag 2 S 2 O 3 and Y is Na 3 [Ag(S 2 O 3 ) 2 ] Correct Option: B

51 Question ID: 5124 Q 113.Identify A, B and C A. Na 2 S 2 O 3, Na 2 [Fe(CN) 5 NOS], CdSO 4 respectively B. Na 2 S, Na 4 [Fe(CN) 5 NOS], CdS respectively C. Na 2 S, Na 2 [Fe(CN) 5 NOD], CdS respectively D. Na 2 S, [Fe(H 2 O) 5 NO]SO 4, Cds respectively Correct Option: B Question ID: 5125 Q 114.A metal M forms water soluble MSO 4 and inert MO.MO in aqueous solution forms insoluble M(OH) 2 which is soluble in NaOH. Metal M is A. Be B. Mg C. Ca

52 D. Si BeO is inert. is water soluble Question ID: 5126 Q 115.The metallic sodium dissolve in liquid ammonia to form a deep blue coloured solution. The deep blue colour is due to formation of : A. Solvated electron, B. Solvated atomic sodium, C. D. Solvated electron is responsible for the blue colour. Question ID: 5127 Q 116.The solubilities of carbonates decrease down the magnesium group due to decrease in A. lattice energies of solids B. hydration energies of cations C. inter-ionic attraction

53 D. entropy of solution formation Correct Option: B Down the group, hydration energy of cation decrease so solubility of carbonates decrease down the group. Question ID: 5128 Q 117.The substance not likely to contain CaCO 3 is A. a marble statue B. calcined gypsum C. sea shells D. dolomite Correct Option: B Calcinated gypsum is anhyd. Question ID: 5129 Q 118.Beryllium and aluminium exhibit many properties which are similar. But, the two elements differ in A. exhibiting maximum covalency in compounds B. exhibiting amphoteric nature in their oxides C. forming covalent halides D. forming polymeric hydrides

54 No Explanation Question ID: 5130 Q 119.Following statements regarding the periodic trends of chemical reactivity of the alkali metals and the halogens are given. Which of these statements give the correct picture? A. In both the alkali metals and the halogens the chemical reactivity decreases with increase in atomic number down the group B. Chemical reactivity increases with increase in atomic number down the group in both the alkali metals and halogens C. In alkali metals the reactivity increases but in the halogens it decreases with increase in atomic number down the group D. The reactivity decreases in the alkali metals but increases in the halogens with increase in atomic number down the group Correct Option: B In alkali metals the reactivity depends on the 1 st ionisation enthalpy (which decreases down the group). So, the chemical reactivity of alkali metals increases down the group. The reactivity of halogens depend on the bond energy and electron gain enthalpy. Thus, the reactivity of halogens decreases down the group. Question ID: 5131 Q 120.When MgSO 4 and NH 4 Cl are added along with Na 3 PO 4, a white precipitate is formed. What is it? A. Mg(NH 4 )PO 4 B. MgSO 4. MgCl 2 C. Mg 3 (PO 4 ) 2 D. MgSO 4. Mg(PO 4 ) 2

55 Question ID: 5132 Q 121.Bleaching powder is obtained by the interaction of Cl 2 and A. dry slaked lime B. hot Ca (OH) 2 C. cold Ca(OH) 2 D. conc. CaCl 2 Question ID: 5133 Q 122.Which is most basic in character? A. CsOH B. KOH C. NaOH D. LiOH CsOH is the strongest base.

56 Question ID: 5134 Q 123.Baking powder contains : A. NaHCO 3, Ca (H 2 PO 2 ) 2 and starch B. NaHCO 3, Ca(H2PO 2 ) 2 C. NaHCO 3, starch D. NaHCO 3 No Explanation Question ID: 5135 Q 124.Which is not true is respect of beryllium chemistry? A. Beryllium is amphoteric B. It forms unusual carbide Be 2 C C. Be(OH 2 ) 2 is basic D. Beryllium halides are electron deficient No Explanation Question ID: 5136 Q 125.Electrolysis of fused anhydrous KCl. MgCl 2. 6 H 2 O gives A. Potassium only B. Magnesium only C. Magnesium and chlorine

57 D. Potassium and magnesium Mg is formed at cathode and is evolved at anode. Question ID: 5137 Q 126.Which of the following substance is used for drying gases? A. Calcium carbonate B. Sodium carbonate C. Sodium bicarbonate D. Calcium oxide Correct Option: D CaO is a drying agent for neutral and basic gases. Question ID: 5138 Q 127.Bleaching powder loses its power on keeping for a long time because A. it changes into calcium hypochlorate B. it changes into CaCl 2 and Ca(OH) 2 C. it absorbs moisture D. it changes into calcium chloride and calcium chlorate Correct Option: D

58 No Explanation Question ID: 5139 Q 128.When one mole of bleaching powder is completely decomposed, then the mass of chlorine gas liberated will be A g B g C g D g Correct Option: B Question ID: 5140 Q 129.The effective component of bleaching powder is A. B. C. D. Correct Option: B

59 is the effective component of bleaching powder Question ID: 5141 Q 130.The product obtained on fusion of BaSO 4 and Na 2 CO 3 is A. BaCO 3 B. BaO C. Ba(OH) 2 D. BaHSO 4 Question ID: 5142 Q 131.The metal with highest specific heat is A. Be B. Al C. Ag D. Au Out of the given four metals, Be has highest specific heat (metal with lowest atomic mass will have highest specific heat )..

60 Question ID: 5143 Q 132.NaOH is prepared by the method A. Down's cell B. Castner cell C. Solvay process D. Castner - Kellner cell Correct Option: D Caustic soda, also called sodium hydroxide is a very strong base. It is called caustic soda because of its corrosive (or irritating ) effect on the skin. Actually it breaks down the proteins present in the skin. Question ID: 5144 Q 133.Nelson's cell is employed for A. manufacture of caustic soda B. manufacture of brine C. manufacture of sodium D. manufacture of potassium dichromate Caustic soda, also called sodium hydroxide is a very strong base. It is called caustic soda because of its corrosive (or irritating ) effect on the skin. Actually it breaks down the proteins present in the skin. Question ID: 5145 Q 134.Which reaction occurs at cathode in Nelson's cell? A. B.

61 C. D. Caustic soda, also called sodium hydroxide is a very strong base. It is called caustic soda because of its corrosive (or irritating ) effect on the skin. Actually it breaks down the proteins present in the skin. Question ID: 5146 Q 135.Sodium carbonate can be manufactured by Solvay's process but potassium carbonate cannot be manufactured because A. KHCO 3 is more soluble than NaHCO 3 B. KHCO 3 is less soluble than NaHCO 3 C. K 2 CO 3 is more soluble than Na 2 CO 3 D. K 2 CO 3 is less soluble than Na 2 CO 3 This is because is more soluble than. Question ID: 5147 Q 136.The purpose of adding CaF 2 to CaCl 2 in the electrolytic process for the extraction of calcium of A. to decrease the m.p. B. to increase the m.p. C. to accelerate the process D. to retard the process

62 The function of is to lower the fusion temperature of Question ID: 5148 Q 137.Halides of alkaline earth metals form hydrates such as MgCl 2. 6H 2 O, CaCl 2. 6 H 2 O, BaCl 2. 2 H 2 O and SrCl 2. 2H 2 O. This shows that halides of group 2 elements: A. act as dehydrating agents B. are hygroscopic in nature C. can absorbs moisture from air D. all the three Correct Option: D All the three properties are correct. Question ID: 5149 Q 138.Sodium reacts with water more vigorously that lithium because A. it has higher atomic weight B. it is more electronegative C. it is more electropositive D. it has higher ionization energy This is because of more electropositive nature of sodium.

63 Question ID: 5150 Q 139.Caesium oxide will be A. very strongly basic B. acidic C. weakly basic D. neutral is strongly basic. Question ID: 5151 Q 140.Which of the following is the strongest base? A. LiOH B. NaOH C. KOH D. CsOH Correct Option: D Alkali metals hydroxides (except lithium hydroxide) are strongest of all bases, highly soluble in water and are not decomposed on heating. However, lithium hydroxide decomposes on heating to give lithium oxide because of greater stability of than LiOH

64 Question ID: 5152 Q 141.Which is formed when potassium is burnt in excess of air? A. K 2 O B. KO C. KO 2 D. K 2 O 2 Potassium forms superoxide Question ID: 5153 Q 142.The correct sequence of increasing covalent character is represented by A. LiCl < NaCl < BeCl 2 B. BeCl 2 < LiCl < NaCl C. NaCl < LiCl < BeCl 2 D. BeCl 2 < NaCl < LiCl Smallter the cation size, greater is its polarising power and more is covalent character (Fazan rule). Since the cation size is in the order. Thus covalent nature is in the order : NaCl < LiCl < BeCl 2 Question ID: 5154 Q 143.Which one is used as an air purifier in space craft? A. Quick lime B. Potassium super oxide

65 C. Caustic soda D. Sylvine Correct Option: B No Explanation Question ID: 5155 Q 144.Which of the following does not form an oxide on heating? A. Na 2 CO 3 B. CaCO 3 C. MgCO 3 D. Li 2 CO 3 is stable towards heating. Question ID: 5156 Q 145.On heating with oxygen, lithium forms A. Oxide B. Peroxide C. Superoxide D. all the three

66 Lithium forms oxide on heating with air. Question ID: 5157 Q 146.Na and K metals never occur in the native state because A. they are unstable B. their chemical activity is very high C. their compounds with other elements are highly stable D. none of these Correct Option: B The elements of groups 1 and 2 are known as s-block elements as the last electron in these enters the valence s- subshell. The elements of group 1 are : Li-Lithium Na- Sodium K-Potassium Rb - Rubidium Cs - Caesium Fr - Francium Lithium was discovered by Arfwedson (1817): Sodium and potassium by Davy (1807): rubidium and caesium by Bunsen (in 1861 and 1860 respectively). and francium by Perey (1939) Due to high chemical reactivity these do not occur free in the nature (native state). General electronic configuration of alkali metals is : [Noble gas ] and of alkaline earth metals is : [Noble gas ] Alkali metals are so named because they dissolve in water to form soluble hydroxides called alkalies. Group 2 elements are known as alkaline earth metals as their oxides are alkaline and occur in earth crust. Question ID: 5158 Q 147.Which electronic configuration is / are not for an alkali metal? A. 1s 2 2s 1 B. 1s 2 2s 2 2p 6 3s 1 C. 1s 2 2s 2 2p 6 3s 2 3p 6 3d 10 4s 1 D. all of these

67 The elements of groups 1 and 2 are known as s-block elements as the last electron in these enters the valence s- subshell. The elements of group 1 are : Li-Lithium Na- Sodium K-Potassium Rb - Rubidium Cs - Caesium Fr - Francium Lithium was discovered by Arfwedson (1817): Sodium and potassium by Davy (1807): rubidium and caesium by Bunsen (in 1861 and 1860 respectively). and francium by Perey (1939) Due to high chemical reactivity these do not occur free in the nature (native state). General electronic configuration of alkali metals is : [Noble gas ] and of alkaline earth metals is : [Noble gas ] Alkali metals are so named because they dissolve in water to form soluble hydroxides called alkalies. Group 2 elements are known as alkaline earth metals as their oxides are alkaline and occur in earth crust. Question ID: 5159 Q 148.Which of the following is a man made element? A. Rb B. Fr C. Cs D. Li Correct Option: B The elements of groups 1 and 2 are known as s-block elements as the last electron in these enters the valence s- subshell. The elements of group 1 are : Li-Lithium Na- Sodium K-Potassium Rb - Rubidium Cs - Caesium Fr - Francium Lithium was discovered by Arfwedson (1817): Sodium and potassium by Davy (1807): rubidium and caesium by Bunsen (in 1861 and 1860 respectively). and francium by Perey (1939) Due to high chemical reactivity these do not occur free in the nature (native state). General electronic configuration of alkali metals is : [Noble gas ] and of alkaline earth metals is : [Noble gas ] Alkali metals are so named because they dissolve in water to form soluble hydroxides called alkalies. Group 2 elements are known as alkaline earth metals as their oxides are alkaline and occur in earth crust.

68 Question ID: 5160 Q 149.Potassium was discovered by A. Davy B. Perey C. Bunsen D. Arfwedsen The elements of groups 1 and 2 are known as s-block elements as the last electron in these enters the valence s- subshell. The elements of group 1 are : Li-Lithium Na- Sodium K-Potassium Rb - Rubidium Cs - Caesium Fr - Francium Lithium was discovered by Arfwedson (1817): Sodium and potassium by Davy (1807): rubidium and caesium by Bunsen (in 1861 and 1860 respectively). and francium by Perey (1939) Due to high chemical reactivity these do not occur free in the nature (native state). General electronic configuration of alkali metals is : [Noble gas ] and of alkaline earth metals is : [Noble gas ] Alkali metals are so named because they dissolve in water to form soluble hydroxides called alkalies. Group 2 elements are known as alkaline earth metals as their oxides are alkaline and occur in earth crust. Question ID: 5161 Q 150.The alkali metal with lowest melting point is A. Fr B. Cs C. Rb D. Na

69 Down the group melting point decreases. Question ID: 5162 Q 151.The lightest metal known as A. Beryllium B. Lithium C. Sodium D. Hydrogen Correct Option: B No Explanation Question ID: 5163 Q 152.All the elements of group 1 are metals except A. Hydrogen B. Lithium C. Sodium D. Rubidium Hydrogen is a non-metal. Question ID: 5164 Q 153.Which metal does not react with nitrogen to form nitride?

70 A. Li B. Mg C. Both Li and Mg D. Cs Correct Option: D and Cs does not react with Question ID: 5165 Q 154.Na crystallizes in. lattice A. fcc B. bcc C. ccp D. hcp Correct Option: B BCC Question ID: 5166 Q 155.Alkali metal that reacts with nitrogen directly to form nitride is : A. Li B. Na C. K D. Rb

71 Lithium forms lithium nitride Question ID: 5167 Q 156.Which of the following has the maximum lattice enthalpy? A. RbF B. CsF C. NaF D. KF For the same anion ion has the smallest size. Question ID: 5168 Q 157.Which statement is false in case of alkali metals? A. Lithium is the strongest reducing agent B. Sodium hydroxide is amphoteric in nature C. ion is exceptionally small D. All alkali metals give blue colour in liquid ammonia Correct Option: B

72 Alkali hydroxides are strong bases and sodium hydroxide cannot be amphoteric in nature. Question ID: 5169 Q 158.The affinity of sodium with water is used in A. drying of alcohols B. drying of ammonia C. drying of benezene D. drying most of the compounds Sodium can be used to dry benzene since it does not react with benzene. Question ID: 5170 Q 159.Fire which results from the combustion of alkali metals can be extinguished by A. CCl 4 B. Sand C. Water D. Kerosene Only flammable. is highly non-inflammable and is suitable. Sand contains some moisture while kerosene is highly

73 Question ID: 5171 Q 160.Which is maximum reactive towards water? A. Li B. K C. Na D. Rb Correct Option: D Reactivity with water increases down the group of alkali metals. Question ID: 5172 Q 161.Lithium shows diagonal relationship with A. Magnesium B. Beryllium C. Aluminium D. Boron Lithium and magnesium are diagonally related. Question ID: 5173 Q 162.Which has the maximum electropositive character? A. Cu B. Cs C. Ba D. Cr

74 Correct Option: B Cs being an alkali metal is strongly electropositive in nature. Question ID: 5174 Q 163.The electronic configuration of a metal M is 1s 2 2s 2 2p 6 3s 1. the formula of its oxide would be : A. MO B. M 2 O C. M 2 O 3 D. MO 2 Correct Option: B The metal M are valency 1 and its oxide will be. Question ID: 5175 Q 164.Which has the maximum m.p? A. NaCl B. NaF C. NaBr D. NaI Correct Option: B

75 NaF is maximum ionic and has highest melting point. Question ID: 5176 Q 165.Which electronic configuration corresponds to least ionization enthalpy? A. 1s 2 2s 2 2p 3 B. 1s 2 2s 2 2p 5 C. 1s 2 2s 2 2p 6 D. 1s 2 2s 2 2p 6 3s 1 Correct Option: D Electronic configuration of alkali metals corresponds to least energy. Question ID: 5177 Q 166.Which is formed when lithium is heated in air? A. Only Li 2 O B. Only Li 3 N C. Both Li 2 O and Li 3 N D. Both Li 2 O 2 and Li 3 N and are formed.

76 Question ID: 5178 Q 167.Sodium does not show an oxidation state of +2 because of its A. high first ionization enthalpy B. high second ionization enthalpy C. large ionic radius D. high electronegativity Correct Option: B Due to low these metals lose their valence s-electron to form unipositive ion and show only +1 oxidation state. Alkali metal ions with no unpaired electrons are diamagnetic and colourless (except permanganates and dichromates where the anions are coloured) +2 oxidation state is not possible due to high Question ID: 5179 Q 168.Alkali metals in each period have A. smallest size B. lowest ionization enthalpy C. highest electron affinity D. highest electronegativity Correct Option: B No Explanation Question ID: 5180 Q 169.In view of their low ionization enthalpies, the alkali metals are A. Weak oxidising agents B. Strong reducing agents

77 C. Strong oxidising agents D. Weak reducing agents Correct Option: B No Explanation Question ID: 5181 Q 170.Which of the following properties is not true for an alkali metal? A. Low atomic volume B. Low ionization enthalpy C. Low density D. Low electronegativity Atomic volume of an alkali metal is high due to low density (Atomic mass = ) Question ID: 5182 Q 171.Which alkali metal ion as lowest mobility in aqueous solution? A. B. C. D.

78 Due to smallest size in aqueous solution is hydrated most so it has lowest mobility. Question ID: 5183 Q 172.A chloride salt of group 1 metal gives a violet colouration in the flame test. It is A. LiCl B. NaCl C. KCl D. CsCl KCl give violet colour to the flame. Question ID: 5184 Q 173.An element having electronic configuration 1s 2 2s 2 2p 6 3s 1 will form A. acidic oxide B. basic oxide C. neutral oxide D. amphoteric oxide Correct Option: B Alkali metals form basic oxide.

79 Question ID: 5185 Q 174.Which of the following increases in magnitude as one move down the group from Li to Cs? A. ionization potential (I.E 1 ) B. ionic radius C. melting point D. hydration of cations Correct Option: B No Explanation Question ID: 5186 Q 175.The alkali metals A. show increasing metallic nature from Li to Cs B. form salts which are predominantly covalent C. show decreased chemical reactivity with dry oxygen in going from Li to Cs D. show increasing electronegativity from Li to Cs No Explanation Question ID: 5187 Q 176.Which of the following reacts with water at a higher rate? A. Li B. Na C. K

80 D. Rb Correct Option: D Order of reactivity of alkali metals with water is Cs > Rb > K > Na > Li Question ID: 5188 Q 177.Alkali metals displace hydrogen from water forming bases due to the reason that A. they are far above the hydrogen in electrochemical series based on oxidation potential B. they are far below the hydrogen in electrochemical series based on oxidation potential C. their ionization potential is less than that of other elements D. they contain only one electron in their outermost shell Correct Option: B Alkali metals are below hydrogen in the electrochemical series based on oxidation potential (in series based on reduction potential, alkali metals are above hydrogen) Question ID: 5189 Q 178.Which hydrated cation is smallest? A. B. C. D. Correct Option: D

81 due to large size is hydrated to least extent. Thus hydrated is smallest. Question ID: 5190 Q 179.The standard oxidation potential of lithium is A V B V C V D V No Explanation Question ID: 5191 Q 180.The increasing order of atomic radius for the elements Na, Rb, K and Li is A. Na < K < Li < Rb B. K < Na < Li < Rb C. Rb < K < Li < Na D. Li < Na < K < Rb Correct Option: D Down the group size increases, so the increasing order of atomic radius is : Li < Na < K < Rb.

82 Question ID: 5192 Q 181.The compound insoluble in acetic acid is A. calcium oxide B. calcium carbonate C. calcium oxalate D. calcium hydroxide Calcium oxalate does not dissolve in acetic acid. All others and are bases and hence dissolve in acetic acid. Question ID: 5193 Q 182.Sodium nitrate decomposes above ~ 800 C to give A. N 2 B. O 2 C. NO 2 D. Na 2 O Correct Option: B Question ID: 5194 Q 183.A certain metal M is used to prepare an antacid, which is used as a medicine in acidity. This metal

83 accidentally catches fire and it was found that the fire cannot be put out by using CO 2 based extinguishers. The metal M is A. Ca B. Na C. Mg D. none Both Mg and Ca fires cannot be extinguished by based extinguishers. However, Mg is used to prepare antiacid suspension of in water. Hence the answer is Mg. Question ID: 5195 Q 184.Ethyl alcohol can be dried with A. CaCl 2 B. Ca C. Na D. none of these Correct Option: B Ethyl alcohol can not be dried with or Na as these react with alcohol Question ID: 5196 Q 185.When sodium is treated with sufficient oxygen / air, the product obtained is

84 A. Na 2 O B. Na 2 O 2 C. NaO 2 D. NaO Correct Option: B Sodium forms peroxide Question ID: 5197 Q 186.Which element has density lesser than water? A. Li B. Rb C. Cs D. Ca Li, Na and K have density lesser than water. Question ID: 5198 Q 187.The reaction of sodium is highly exothermic with water. The rate of reaction is lowered by A. mixing with alcohol B. mixing with acetic acid C. making an amalgam D. lowering the temperature

85 This is because in amalgam, available surface area for reaction is reduced. Question ID: 5199 Q 188.Alkali metal when exposed to air tarnish quickly due to the A. formation of their hydroxides B. formation of their carbonates C. formation of their oxides D. all the above Correct Option: D Alkali metals are so reactive that they tarnish rapidly when exposed to air because of the formation of oxides, hydroxides and ultimately carbonates at the surface. Hence they are kept under inert liquid like kerosene oil which prevents them from coming in contact with air and moisture. Here, M - Alkali metal Different alkali metals combine with oxygen on heating to from different oxides e.g. Question ID: 5200 Q 189.Alkali metal halides except Li are soluble in water showing that they are A. ionic compounds

86 B. covalent compounds C. double salts D. coordination compounds No Explanation Question ID: 5201 Q 190.Natrium is kept in A. water B. kerosene C. alcohol D. ammonia Correct Option: B Natrium (sodium is kept under kerosene oil to avoid the reaction with air / water. Question ID: 5202 Q 191.Potassium cannot be kept under A. benzene B. CCl 4 C. kerosene D. alcohol Correct Option: D