SECTION A (40 Marks) Compulsory: Attempt all questions.

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1 Question 1 (a) SETION (40 Marks) ompulsory: ttempt all questions. Directions: Each question in this part is followed by four possible choices of answers. hoose the correct answer and write it in the space provided in the question booklet. [15] In the periodic table, alkali metals belong to group D 4. ll of the following are the examples of polar covalent molecules EXEPT D 2O. N3. l. l4. (iii) The general formula of alkyne is n2n-2. Which of the following is an example of an alkyne? D ethane ethylene methane acetylene (iv) n experiment was carried out to find the action of sodium hydroxide with a salt solution. fter the experiment, a reddish brown precipitate was observed due to the formation of D ferrous hydroxide. ferrous chloride. ferric hydroxide. ferric chloride. SE/he/2015 Page 3 of 20 opyright Reserved

2 (v) Which of the following statements best describes the characteristics of electronegativity? I. Electro negativity increases across the period. II. Electro negativity decreases across the period. III. Electro negativity increases down the group. IV. Electro negativity decreases down the group. D I and III I and IV II and III I only (vi) 44 gms of O2 at STP is equivalent to D 11.2 litre litre litre litre. (vii) The relative molecular mass of a substance is 98 amu. This substance is D l. NO3. 2SO4. 2O3. (viii) The most non-metallic element from the following is D boron. carbon. lithium. beryllium. SE/he/2015 Page 4 of 20 opyright Reserved

3 (ix) The atomicity of ozone gas is D 4. (x) The metal rods used to conduct current in electrolysis are called D anodes. cathodes. electrodes. electrolytes. (xi) class X student drew the following diagram to show the laboratory preparation of l gas. l onc.no 3 + Nal onc. 2SO 4 The hemistry Teacher made the student to redraw it because reactants used are not correct. heat is required for the reaction. conc. 2SO4 is used as a dying agent. D gas is collected by upward displacement. SE/he/2015 Page 5 of 20 opyright Reserved

4 (xii) The following equation ZnO+ Zn+O, explains the process of calcination. smelting. roasting. D leaching. (xiii) onc. 2SO4 spilled over a wooden shelf make the portion black due to its charring effect. The element responsible for this phenomenon is hydrogen. sulphur. oxygen. D carbon. (xiv) The correct structural formula of propene is D SE/he/2015 Page 6 of 20 opyright Reserved

5 (xv) n acid X is used in the manufacture of fertilizers and anti-rust paints. Identify the acid. hydrochloric acid phosphoric acid carbonic acid D nitric acid (b) Match each item under olumn with the most appropriate item in olumn. Rewrite the correct matching pairs in the spaces provided below. [5] olumn N N 3+5O 2 (iii) 2SO 2+O 2 2N 3+eat Pt / Rh 4NO+6 2O+heat Pt / V2O SO 3 (iv) Empirical formula (v) Number of moles present in 11.2 litre olumn a. 1 mole b. 2O2 c. 0.5 mole d. aber process e. Ostwald process f. 2SO4 g. ontact process (c) Fill in each blank by choosing the appropriate word given in the bracket. [5] n atom Y with an atomic number 11 falls in... group of the modern periodic table. (I / II) The number of water molecules present in 1.8 gm of water is... (iii) ( / ) The most preferable electrolyte used for the electroplating of an article with silver is... (Na [g(n)2] / g NO3) (iv) The metal which can displace hydrogen from dilute acids is... (zinc / copper) (v) base which can easily dissolve in water is... (u(o)2 / KO) SE/he/2015 Page 7 of 20 opyright Reserved

6 (d) orrect the following statements by changing only the underlined words. Rewrite the correct statements. [6] The valency of an element belonging to the third period and group VI in the periodic table is one. alcium chloride is formed by coordinate bonding. (iii) Salts that consist of more than one cation or anion in their aqueous solutions are basic salts. (iv) The gas liberated when a conc. alkali is treated with a zinc metal is chlorine. (v) The combination of 15 m 3 of nitrogen with 20 m 3 of hydrogen results in the formation of 30 m 3 of ammonia. (vi) The dehydration process includes addition of methanol, pyridine or uso4 to ethyl alcohol. (e) Give reasons. [6] student was provided with solid Nal to carry out the process of electrolysis. owever, the student was unable to perform the experiment. SE/he/2015 Page 8 of 20 opyright Reserved

7 For the laboratory preparation of conc. NO3, Karma was provided with two reagents conc. 2SO4 and conc. l. owever, Karma used only conc. 2SO4. (iii) Pema preferred aluminium over copper for making transmission wires. (f) nswer the following questions: [3] Draw an electron dot structural diagram for calcium oxide. The number of times a molecule of the substance is heavier than 1 12 th of the mass of the carbon (-12) atom. What does the statement define? (iii) If the IUP name of 322O is propan-1-ol, what will be its common name? SE/he/2015 Page 9 of 20 opyright Reserved

8 SETION (40 Marks) ttempt any four questions. Question 2 (a) Name the following based on the descriptions given. [3] Salt formed upon reaction between aluminium and sodium hydroxide solution. The electron pair acceptor species in the formation of ammonium ion. (iii) leaching agent that occurs due to oxidation and has a permanent effect. (b) Find out the percentage composition of potassium in potassium ferrocyanide, K4 [Fe(N)6]. [2] Distinguish between flux and slag in the table given below: [2] Flux Slag SE/he/2015 Page 10 of 20 opyright Reserved

9 (c) omplete and balance the following chemical equations: [3] 25O + Na 25O + O2 O +... O +... Question 3 (a) Given below is a list of elements. [3] (b) [neon, boron, sodium, carbon, fluorine, lithium] Which of these elements has the smallest size? Identify the strongest oxidising agent. (iii) Name the element with zero value of electron affinity. compound on analysis contains 54.5% carbon, 9.12% hydrogen and the rest is oxygen. If its vapour density is 44, determine its empirical formula. [2] calculate the molecular formula of the compound. [2] SE/he/2015 Page 11 of 20 opyright Reserved

10 (c) Mention one use for each of the following: [3] Ethanol Nitric acid (iii) Sulphuric acid Question 4 (a) The questions given below refer to the electrolysis of aqueous solution of copper sulphate using copper electrodes. (b) oth 2 SO 4 and ions migrate to the anode. ut none of these ions gets discharged at the anode. Why? [1] ow does the reactions differ at the cathode and anode? [2] What do you observe when dilute hydrochloric acid is added to lead nitrate solution? [1] ammonia gas is burnt in an atmosphere of oxygen in the absence of a catalyst. [1] SE/he/2015 Page 12 of 20 opyright Reserved

11 (c) In the laboratory preparation of ammonia gas, the temperature in the catalyst chamber should not exceed above 500 o. Explain why. [2] (iii) From the equation: 2NaO3 300 Na2O3 + O2 + 2O, calculate the mass of sodium carbonate obtained on heating 1.68 gm of sodium bicarbonate to 300 o. [3] Question 5 (a) nswer the following questions on the extraction of aluminium metal from its ore. What happens when the ore is heated with conc. caustic soda under pressure at 150 o? Explain your answer with the help of a balanced equation. [2] Name the impurity that dissolves during the extraction. Write the chemical equation to support your answer. [2] SE/he/2015 Page 13 of 20 opyright Reserved

12 (b) Study the elements given below and answer the questions that follow: W 3 X 11Y 5Z ompare the size of the elements X 7 and Z 11. [1] The ionisation energy of the element Y is lesser than X. Why? [1] (iii) Is the element 24 12W a metal or a non-metal? Explain why. [2] (c) From the chemical reactions, X X e and Y e Y, write the reaction that undergoes oxidation. reduction. Question 6 (a) Define the following terms: [4] ovalency qua regia [2] SE/he/2015 Page 14 of 20 opyright Reserved

13 (b) (iii) Precipitate (iv) Electro metallurgy You have made a set up as shown below. SO 2 gas fter sometime, what change would you observe in diagram? Give a reason to support your answer. [2] cidified potassium dichromate What would you observe, if the solution in diagram is replaced with a universal indicator? Give a reason. [2] SE/he/2015 Page 15 of 20 opyright Reserved?

14 (c) lcohol plays an important role in our life. Do you agree with the statement? Justify your answer. Question 7 (a) alculate the number of atoms and volume occupied by 2.5 moles of SO2 at STP. [2] [3] List two conditions required for the electroplating of an article with metal X. [2] (iii) What is the colour of the precipitate formed, when 2S gas is bubbled through an aqueous solution of uso4? [1] (b) Identify the cation formed upon dissociation of the following compounds: [2] leaching powder arbonic acid SE/he/2015 Page 16 of 20 opyright Reserved

15 (c) In the industrial preparation of 2SO4, both Pt and V2O5 can be used as catalysts. Which catalyst is more preferable? Justify. [2] tomic weights of elements Elements tomic weights Elements tomic weights ydrogen 1 Phosphorus 31 elium 4 Sulphur 32 Lithium 7 hlorine 35.5 eryllium 9 Potassium 39 arbon 12 alcium 40 Nitrogen 14 Iron 56 Oxygen 16 opper 63.5 Magnesium 24 Zinc 65 luminium 27 romine 80 Silicon 28 SE/he/2015 Page 17 of 20 opyright Reserved

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