PHYSICAL CHEMISTRY By:- Shailendra kumar

Transcription

1 PHYSICAL CHEMISTRY By:- Shailendra kumar H :- PP KHUDA BAKSH LIBRARY, ASHK RAJPATH, PATNA - 4 B: House No 5A/65, pp Mahual Kothi, Alpana Market, Patna CNFIDENCE BUILDING TEST Convert 05 M KMn 4 in gm/liter (Mol wt of KMn 4 = 158) 2 Calculate no of DZEN in 60 mango 3 Calculate no of mol of Na + in ion Na + 4 Calculate no of H + per ml in 10 5 M H 2 5 Calculate no of H + per ml in 10 5 M HCl 6 Calculate molarity of H + in resulting solution when 100 ml of M H 2, 100 ml of M HCl and 100 ml of M HN 3 mixed 7 In the above problem (Q N = 6) calculate no of H + and no of mol of H + in resulting solution 8 Calculate no of molecule of C 2 in 440 amu C 2 9 Calculate wt of one molecule of C 2, C 6 H 12 6 and C in gm gm C 6 H 12 6 dissolved in water and make 250 ml solution 25 ml of this solution diluted ten times Calculate no of C atom in final solution 11 Match the following choosing one item from column [X] and the appropriate item from column [y] [X] wt [Y] (a) Dilution (i) 1000 Mol wt (b) No of milli mol (ii) wt 1000 Mol wt V (ml) (c) Molarity (iii) MV = Constant (d) No of mol (iv) No of particle DZEN 12 particle (e) No of DZEN (v) No of molecule N A molecule mol (f) amu (g) Wt of one mol C 6 H 12 6 (vi) 180 gm (vii) gm

2 CNFIDENCE BUILDING TEST Give the number of moles of each element present in 10 mol of each of the following substances: (a) NH 3 (b) N 2 H 4 (c) (NH 4 ) 2 Cr 2 7 (d) CoCl 2 6H 2 2 How many atoms of each element are present in 10 mol of each of the substances in Ques no 1? 3 How many grams of each element are present in 10 mol of the substances in Question no 1? 4 How many moles of each element are present in 10 mol of the substances in Question no 1? 5 How many atoms of each element are present in 10 mol of the substances in Question no 1? 6 Determine the mass in grams of : (a) N 2 molecules (b) mol of N 2 (c) mol of N 2 (d) a single N 2 molecule 7 Aluminum metal is produced by passing an electric current through a solution of aluminum oxide (Al 2 3 ) dissolved in molten cryolite (Na 3 AlF 6 ) Calculate the molecular weights of Al 2 3 and Na 3 AlF 6 8 Ascorbic acid, or vitamin C (C 6 H 8 6 ), is an essential vitamin It cannot be stored by the body and must be present on the diet What is the molecular weight of ascorbic acid? Vitamin C tablets are often taken as a dietary supplement If a typical tablet contains 5000 mg of vitamin C, how many moles and how many molecules of vitamin C does it contain? 9 How many moles are represented by each of these samples? (a) 100 molecules (exaclty) of H 2 (b) 1000 g of H 2 (c) 500 atoms (exactly) of Fe (d) 5000 g of Fe (e) 150 molecules (exactly) of 2 (f) 1500 g of Fe Aspartame is an artificial sweetener that is 160 times sweeter than sucrose (table sugar) when dissolved in water It is marked as Nutra-Sweet The molecular formula of aspartame is C 14 H 18 N 2 5 (a) Calculate the moleculer weight of aspartame (b) How many moles of molecules are in 100 g of aspartame? (c) What is the mass in grams of 156 mol of aspartame (d) How many molecules are in 50 mg of aspartame? (e) How many atoms of nitrogen are in 12 g of aspartame? (f) What is the mass in grams of molecules of aspartame? (g) What is the mass in grams of one molecule of aspartame? 11 The molecular formula of acetylsalicylic acid (aspirin), one of the most commonly used pain relievers, is C 9 H 8 4 (a) Calculate the molecular weight of aspirin (b) A typical aspirin tablet contains 500 mg of C 9 H 8 4 How many moles of C 9 H 8 4 molecules and how many molecules of acetyl salicylic acid are in a 500-mg tablet? 12 Chloral hydrate (C 2 H 3 Cl 3 2 ) is a drug that is used as sedative and hypnotic (a) Calculate the molecular weight of chloral hydrate (b) How many moles of C 2 H 3 Cl 3 2 molecules are in 5000 g of chloral hydrate? (c) What is the mass in grams of mol of chloral hydrate? (d) How many chlorine atoms are in 50 g of chloral hydrate? (e) What mass of chloral hydrate would contain 10 g of Cl? (f) What is the mass of exactly 500 molecules of chloral hydrate? 13 Calculate the molecular weight of each of the following substances: (a) CuCl 2 6H 2 (The 6H 2 indicates the presence of six water molecules) (b) NaBr 3 (c) (C 2 F 4 ) 500 (the polymer Teflon), which is made of the unit : F F C C F F 14 How many atoms of carbon are present in 10 g of each of the following? (a) CH 4 (b) CH 3 C 2 H (c) Na 2 C 3

3 15 Vitamin B 12, cyanocobalamin, is essential for human nutrition It is concentrated in animal tissue but not in higher plants Although nutritional requirements for the vitamin are quite low, people who abstain completely from animal products may develop a deficiency anemia Cyanocobalamin is the form used in vitamin supplements It contains 434% cobalt by mass Calculate the molecular weight (molar mass) of cyanocobalamin assuming there is one atom of cobalt in every molecule of cyanocobalamin 16 Hemoglobin is the protein that transports oxygen in mammals Hemoglobin is 0342% Fe by mass, and each hemoglobin molecules contains four iron atoms Calculate the molecular weight (molar mass) of hemoglobin 17 A student prepares a solution by dissolving 475 g of solid KH in enough water to make 275 ml of solution (a) Calculate the molarities of the major ionic species present (b) Calculate the molarities of the major ionic species present if 2500 ml of this solution is added to a 100-mL volumetric flask and water us added to the mark 18 What species are present in solution when the following compounds are dissolved in water? (a) ammonium sulfate; (b) Carbon dioxide: (c) sodium fluoride; (d) potassium carbonate; (e) sodium hydrogensulfate; and (f) chlorine 19 Aqueous solutions of potassium permanganate are often used in general chemistry laboratories A laboratory instructor weighed out 4741 g of KMn 4, added the solid to a 200-L volumetric flask, and filled to the mark with water A 5000-mL sample was removed from the volumentric flask and mixed with enough water to make 1500 L of solution What was the final molarity of the KMn 4 solution? 20 Vitamin B 12 is a large molecule called cobalamin There is one atom of cobalt in each molecule of vitamin B 12, and the mass percent of cobalt is 434% Calculate the molar mass of cobalamin 21 A worker in a biochemistry laboratory needed a solution that was 030 M in sodium acetate (NaCH 3 C 2 ) and 015 M in acetic acid (CH 3 C 2 H) n hand were stock solutions of 50 M solution acetate and 50 M acetic acid Describe how the worker prepared 15 L of the desired solution 22 The density of pure water is 10 g/ml Calculate the molar concentration of water molecules in pure water 23 Plants can be badly damaged by solutions that are highly concentrated A biochemist friend of the urban gardener recommends against using fertilizer solution that are greater than 10 mm ( M) in total nitrogen If the gardener wants to prepare 750 ml of 10 mm fertilizer solution, how many milliliters of the stock solution will be need to make the desired solution? 24 When aqueous solutions are used for intravenous infusions, it is essential that the molarity of the solution match the molarity of blood Blood is approximately 031 M, so a solution of sodium chloride for infusion, called saline, must have a concentration of 0155 M Calculate the mass of NaCl that solution be used to prepare 500 L of a 100 M stock solution, and then calculate how many milliliters of the resulting stock solution must be diluted to give 455 ml of 0155 M solution for infusion Solution 1 (a) 10 mol N; 30 mol H; (b) 20 mol N; 40 mol H; (c) 20 mol N; 80 mol H; 20 mol Cr; 70 mol ; (d) 10 mol Co; 20 mol Cl; 12 mol H; 60 mol ; 2 (a) atoms N; atoms H; (b) atoms N; atoms H; (c) atoms N; atoms H; atoms Cr; at oms ; (d) atoms Co; atoms Cl; atoms H; atoms ; 3 (a) 14 g N; 30 g H; (b) 28 g N; 40 g H; (c) 28 g N; 80 g H; g Cr; g ; (d) 59 g Co; 71 g Cl; 12 g H; 96 g ; 4 (a) mol N; mol H; (b) mol N; mol H; (c) mol N; mol H; mol Cr; mol ; (d) mol Co; mol Cl; mol H; mol ; 5 (a) atoms N; atoms H; (b) atoms N; atoms H; (c) atoms N; atoms H; atoms Cr; atoms ; (d) atoms Co; atoms Cl; atoms H; atoms ; 6 (a) g N 2 ; (b) g N 2 ; (c) g N 2 ; (d) g N 2 ; 7 Al 2 3, 1020 g/mol; Na 3 AlF 6 ; 2100 g/mol; mol; molecules; 9 (a) mol (100 is exact) (b) 5549 mol; (c) mol (500 is exact) (d) 8953 mol; (e) mol (150 is exact) (f) mol; 10(a) 294 g/mol (b) mol; (c) 459 g; (d) molecules (e) atoms of nitrogen; (f) g or 490 fg; (g) g/molecule 11 (a) 1800 g/mol; (b) mol; molecules; 12(a) 1654 g/mol; (b) 3023 mol; (c) 33 g (d) atoms of chlorine (e) 16 g chloral hydrate (f) g 13(a) 2425 g/mol (b) 1509 g /mol (c) g/mol 14(a) atoms of C; (b) atoms (c) atoms g/ mol g/mol 17 (a) [K + ] = [H ] = 0308 M (b) [K + ] = [H ] = 0077 M 2 18 (a) H 2, NH 4+, (b)h 2,C 2 (c) H 2, Na +, F (d) H 2, K + 2, C 3, (e) H 2, Na +, HS 4, (f) H 2, Cl M g/mol 21 Mix 0090 L of sodium acetate solution, 0045 liter of acetic acid solution and enough water to make the final volume 15 liter M ml g, 75 ml

4 CHEMISTRY By:- Shailendra Kumar H :- PP KHUDA BAKSH LIBRARY, ASHK RAJPATH, PATNA - 4 B: House No 5A/65, pp Mahual Kothi, Alpana Market, Patna CNFIDENCE BUILDING TEST-3 1 Which of the following is correct? (a) 1 L = 1 dm 3 (b) 1 L = 10 dm 3 (c) 10 L = 1 dm 3 (d) 1 L = 1 m litres of a gas at NTP are found to have a mass of 11 g The molecular mass of the gas is (a) 22 (b) 44 (c) 88 (d) 32 3 How many atoms are present in a mole of H 2? (a) (b) (c) (d) The total number of electrons present in 18 ml of water (density of water is 1 g ml 1 ) is (a) (b) (c) (c) If molecules are removed from 200 mg of C 2, then the number of moles of C 2 left are (a) (b) (c) (d) Number of molecules in 100 ml of each of 2, NH 3 and C 2 at STP are (a) in the order C 2 < 2 < NH 3 (b) in the order NH 3 < 2 < C 2 (c) the same (d) NH 3 = C 2 < 2 7 A gas is found to have the formula (C) x Its VDis 70 The value of x must be (a) 7 (b) 4 (c) 5 (d) mol of CH 4 contains (a) atoms of H (b) 4 g atoms of hydrogen (c) molecules of CH 4 (d) 30 g of carbon 9 Which one of the following pairs of gases contains the same number of molecules? (a) 16 g of 2 and 14 g of N 2 (b) 8 g of 2 and 22 g of C 2 (c) 28 g of N 2 and 22 g of C 2 (d) 32 g of 2 and 32 g of N 2 10 The number of water molecules in 1 litre of water is (a) 18 (b) (c) N A (d) 5555 N A 11 The number of oxygen atoms in 44 g of C 2 is approx (a) (b) (c) (d) A 5 molar solution of H 2 is diluted from be 1 litre to a volume of 10 litres, the normality of the solution will be: (a) 1 N (b) 01 N (c) 5 N (d) 05 N 13 The number of moles of BaC 3 which contains 15 moles of oxygen atoms is (a) 05 (b) 1 (c) 3 (d) The total number of protons in 10 g of calcium carbonate is (N 0 = ) (a) (b) (c) (d) If N A is Avogadro s number then number of valence electrons in 42 g of nitride ions (N 3 ) is (a) 24 N A (b) 42 N A (c) 16 N A (d) 32 N A 16 Haemoglobin contains 033% of iron by weight The molecular weight of haemoglobin is approximately The knumber of iron atoms (at wt of Fe = 56) present in one molecule of haemoglobin is (a) 6 (b) 1 (c) 4 (d) ml of a sodium carbonate solution contains 265 grams of Na 2 C 3 If 10 ml of this solution is diluted to one litre, what is the concentration of the resultant solution? (mol wt of Na 2 C 3 = 106) (a) 01 M (b) 0001 M (c) 001 M (d) 10 4 M 18 The number of moles of S 2 Cl 2 in 135 g is (a) 01 (b) 02 (c) 03 (d) 04

5 19 The number of atoms in 425 g of NH 3 is approximately (a) (b) (c) (d) Which has maximum molecules? (a) 7 g N 2 (b) 2 g H 2 (c) 16 g N 2 (d) 16 g 2 21 A compound has haemoglobin like structure It has one Fe It contains 46% of Fe The approximate molecular mass is (a) 100 g mol 1 (b) 1200 g mol 1 (c) 1400 g mol 1 (d) 1600 g mol 1 22 Which has maximum number of atoms? (a) 24 g of C (12) (b) 56 g of Fe (56) (c) 27 g Al (27) (d) 108 g of Ag (108) 23 Calculate kb of Cl (Assume ka of HCl is 10 7 ) (a) 10 7 (b) (c) (d) Concentration of H + in 10 7 M HCl solution is approximetely (a) M (b) 10 7 M (c) M (d) 10 8 M 25 Which two of the following solution contains equal ph (1) 50 ml of 010 M HCl + 25 ml H 2 (2) 50 ml of 010 M HCl + 50 ml H 2 (3) 50 ml of 010 M H ml H 2 (4) 25 ml of 010 M H ml H 2 (a) (1) and (4) (b) (1) and (3) (c) (1) and (2) (d) (2) and (3) 26 If 40 ml of 16 M HCl and 60 ml of 20 M NaH are mixed, What are the molar concentrations of Na + (a) 0640 M (b) 12 M (c) 0560 M (d) 065 M 27 Calculate no of millimol of C 2 in 56 liter C 2 at STP (a) 200 (b) 250 (c) 1000 (d) Kb of acetate ion (CH 3 C ) is Ka of acetic acid is (a) (b) (c) (d) Predict the nature of solution is Acidic, Basic or Neutral in following soution of ions (a) Na + (b) CH 3 C (c) Cl + (d) NH 4 (e) K + (f) N 3 30 Calculate weight of oxygen atom in atom oxygen (a) 16 gm (b) 32 gm (c) 160 gm (d) 1600 gm 31 Which of the following reaction explain the basic nature of sodium acetate (CH 3 CNa) (a) CH 3 CNa + H 2 CH 3 CH + NaH Week acid Strong base (b) CH 3 CNa 100% CH 3 C + Na + Na + + H 2 No reaction (No Hydrolysis) CH 3 C + H 2 CH 3 CH+H (c) Na+ + H 2 NaH + H 2 (d) CH 3 C + H + CH 3 CH gm H 2 dissolved in water and make 250 ml solution, molarity of 25 ml of this solution is (a) 0004 M (b) 004 M (c) 04 M (d) 0024 M 33Which of the following is correct representation of + K NH3 (Assume pure NH 3 self ionizes into NH 4 and NH 2 ) (a) K NH3 = [NH 3 ] [NH 2 ] (b) K NH3 = [NH 4+ ] [NH 2 ] (c) K NH3 = [NH 2 ] [NH 2 ] (d) K NH3 = [NH 3 ] [NH 3 ] 34 What is the total concentration of Cl in a mixture that is 020 M MgCl 2, 030 M NaCl and 040 M AlCl 3 (a) 030 M (b) 090 M (c) 280 M (d) 190 M 35 How many moles of Ca(H) 2 are present in 350 ml of 0010 M aqueous solution of Ca(H) 2 (a) 35 (b) 35 (c) (d) In problem (35) what is the molar concentration of Hydroxide ion (a) Zero (b) 0010 M (c) 0021 M (d) M 37 What volume of 0040 M aqueous HCl solution would be required to entirely neutralize the solution in 350 ml of 0010 M aqueous solution of Ca(H) 2 (a) 175 ml (b) 75 ml (b) 350 ml (d) 700 ml

6 A N S W E R S 1 (a) 2 (b) 3 (d) 4 (c) 5 (a) 6 (c) 7 (c) 8 (b) 9 (a) 10 (d) 11 (a) 12 (a) 13 (a) 14 (c) 15 (a) 16 (c) 17 (b) 18 (a) 19 (d) 20 (b) 21 (b) 22 (a) 23 (d) 24 (a) 25 (a) 26 (b) 27 (b) 28 (d) 29 (a) Neutral (b) Basic (c) Neutral (d) Acidic (e) Neutral (f) Neutral 30 (c) 31 (b) 32 (c) 33 (b) 34 (d) 35 (c) 36 (d) 37 (a)

7 CHEMISTRY By:- Shailendra Kumar H : pp Khuda Baksh Library, Ashok RajPath, Patna -4 B: House No 5A/65, pp Mahual Kothi, Alpana Market, Patna Confidence Building Test How many moles of calcium hydroxide are present in 350 ml of a 0010 M aqueous solution of Ca(H) 2? (a) 35 (b) 35 (c) 0010 (d) (e) In Problem 1, what is the molar concentrration of the hydroxide ion? (a) zero (b) 0010 M (c) 0021 M (d) M (e) M 3 What volume of 0040 M aqueous HCl solution would be required to entirely neutralize the solution in Problem 1? (a) 4375 ml (b) 875 ml (c) 175 ml (d) 350 ml (e) 700 ml 4 Suppose 100 ml of 0020 M aqueous H 3 P 4 are added to the solution in Problem 1 Assuming the olumes are additive, what are the concentrations of H species present after reaction? (a) zero (b) M (c) M (d) 0005 M (e) Which of the following would be a satisfactory primary standard for titrating a solution of HCl (aq)? (a) NaH (b) Na 2 C 3 (c) KHP (d) HN 3 (e) HAc 6 In standardizing a solution of NaH (aq) of unknown concentration, 1575 ml of it are required to reach the neturalization point in a reaction with grams of KHP (MW = 2042 g/mol) What is the molar concentration of NaH? (a) M (b) M (c) 0022 M (d) 222 M 7 Identify the INCRRECT statement: (a) ne equovalent of a substance has 1 mole of reactive capability (b) The equivalent weight of a substance is the grams of that substance in one equivalent (c) ne mole of HCl is also one equivalent of HCl (d) An equivalent of acid exactly neutralizes an equivalent of base (e) The Normality of a solution is the number of equivalents per mole of that solution 8 Identify the INCRRECT statement: (a) 245 grams of H 2 is 1/2 of an equivalent of H 2 (b) A 0100 N solution of Ca(H) 2 is 0050 M (c) The equivalent weight of Ca(H) 2 is 74 g/equiv (d) A 60 M solution of H 3 P 4 is 180 N 9 What is the normality of an H 2 solution if 100 ml of it exactly neutralizes 1000 ml of 20 N sodium hydroxide solution? (a) 010 N (b) 020 N (c) 100 N (d) 200 N 10 What is the H 3 + concentration in 10 M NaH? (a) 10 M (b) M (c) M (d) M 11 What is the H concentration in a neutral aqueous solution? (a) exactly zero

8 (b) M (c) 70 M (d) 10 M (e) M 12 A particular vinegar solution has a H 3 + concentration of 0015 M What is the ph the solution (a) 18 (b) 18 (c) 0015 M (d) 33 (e) What is the ph of the solution in problem 12? (a) 107 (b) 173 (c) 122 (d) 158 (e) The Ka of acetic acid is What is its pka? (a) (b) 518 (c) 474 (d) What is the ph of a 0100 M solution of acetic acid? (a) (b) 287 (c) 100 (d) 474 (e) What is the acetate ion (Ac or CH 3 C ) concentration of the solution in Problem 15? (a) exactly zero (b) 374 M (c) 0100 M (d) (e) What is the percent ionization of the acetic acid in Problem 15? (a) 134 % (b) 0134% (c) 00014% (d) % (e) % + 19 What is the NH 4 concentration of the solution in Problem 18? (a) 60 M (b) M (c) M (d) M 20 HN 2 has a pk a = 335 and HCl has a pk a = 745 Which is the stronger acid? (a) HN 2 (b) HCl 21 Based on the information given in Problem 20, what is the K a of HN 2? (a) (b) (c) (d) (e) What is the H 2 species concentration in any dilute aqueous solution? (a) zero (b) infinite (c) 555 M (d) 10 M (e) M 23 Which is the most likely ph of Windex glass cleaner? (a) 2 (b) 4 (c) 7 (d) 12 (e)14 18 What is the ph of 60 N aqueous solution of NH 3 (ammonia) It s K b = (a) (c) 0778 (e) 132 (b) 198 (d) 120

9 A N S W E R S 1 d 2 c 3 c 4 b 5 b 6 a 7 e 8 c 9 d 10 b 11 e 12 a 13 c 14 c 15 b 16 d 17 a 18 d 19 b 20 a 21 d 22 c 23 d

10 Code :- 05 CHEMISTRY By:- Shailendra Kumar H :- pp Khuda Baksh Library, Ashok RajPath, Patna -4 B:- House No 5A/65, pp Mahual Kothi, Alpana Market, Patna Confidence Building Test 05 1 What is the total concentration of Cl in a mixture that is 020 M MgCl 2, 030 M NaCl and 040 M AlCl 3 (a) 030 M (b) 090 M (c) 280 M (d) 190 M 2 How many moles of Ca(H) 2 are present in 350 ml of 0010 M aqueous solution of Ca(H) 2 (a) 35 (b) 35 (c) (d) In problem (2) what is the molar concentration of Hydroxide ion (a) Zero (b) 0010 M (c) 0021 M (d) M 4 What volume of 0040 M aqueous HCl solution would be required to entirely neutralize the solution in 350 ml of 0010 M aqueous solution of Ca(H) 2 (a) 175 ml (b) 75 ml (b) 350 ml (d) 700 ml 5 Suppose 100 ml of 0020 M aqueous H 3 P 4 are added to the solution of 350 ml of 0010 M aqueous solution of Ca(H) 2 Assume the volumes are additive, what are the concentrations of H species present after reaction (a) 1/450 M (b) 1/350 M (c) 13/450 M (d) 6/450 M 6 Identify the incorrect statement (a) ne equivalent of substance has one mol of reactive capability (b) The equivalent weight of a substance is the gram of that substance in one equivalent (c) ne mol of HCl is also one equivalent of HCl (d) The normality of a solution is the number of equivalents per mole of that solution 7 Identify the incorrect statement (a) 245 gm of H 2 is 05 of an equivalent of H 2 (b) 010 N solution of Ca(H) 2 is 0050 M (c) The equivalent weight of Ca(H) 2 is 74 gm/ equivalent (d) A 60 M solution of H 3 P 4 is 180 N 8 What is the normality of an H 2 solution if 100 ml of it exactly neutralizes 100 ml of 20 N sodium hydroxide solution (a) 010 N (b) 020 N (c) 100 N (d) 200 N 9 What is the H 3 + concentration in 10 M NaH? (a) 10 M (b) M (c) M (d) M 10 What is the H concentration in a neutral solution (a) exactly zero (b) M (c) 70 M (d) M 11 The K a acetic acid is , what is its Pk a? (log 18 = 026) (a) (b) 518 (c) 474 (d) What is the ph of 010 M solution of acetic acid (K a of acetic acid = ) (a) (b) 287 (c) 474 (d) What is the percent ionization of the 018 M acetic acid (K a = ) (a) 4% (b) 1% (c) 001% (d) 0001% 14 What is P H of 10 2 M CH 3 C Pk a of acetic acid = 5 (a) 55 (b) 85 (c) 70 (d) 2 15 What is the percent hydration of 01 M acetate ion Pk a of acetic acid = 5 (a) 10 3 % (b) 10 2 % (c) 10 4 % (d) 10 5 % 16 What volume of 015 M HCl can be made from 75 ml of concentrated HCl (12 M) (a) 0060 L (b) 60 L (c) 060 L (d) L 17 How many moles of Mg(H) 2 can be precipitated when 100 ml of 05 M MgCl 2 solution is mixed with 100 ml of 025 M KH (a) 0025 mol (b) 005 mol

11 (c) mol (d) 05 mol 18 The first step in the ostwald process for producing nitric acid, HN 3 from ammonia is represented by this equation 4NH 3 (g) (g) 4N (g) + 6H 2 (g) What volume of oxygen is needed to produce each liter of N? (a) 080 L (b) 50 L (c) 125 L (d) 224 L 19 What volume of 0500 M CaCl 2 solution is needed to prepare 250 ml of solution that has a chloride concentration of 0100 M (a) 125 ml (b) 50 ml (c) 25 ml (d) 100 ml 20 The limiting reagent in a particular reaction can be recognized because it is the reagent (a) with the smallest coefficient in the balanced equation (b) that has the lowest mass in the reaction mixture (c) that is present in the smallest molar quantity (d) that would be used up first 21 How many gram of carbon are present in 050 mol of sucrose (C 12 H ) (a) 60 gm (b) 72 gm (c) 90 gm (d) 120 gm 22 The major commercial source for bromine is deep brine well where the concentration of bromide ion can be high as 5000 ports per million by mass What is this concentration when expressed as a mass percentage? (a) 0005% (b) 05 % (c) 005% (d) 5% 23 The ph of a 0005 M aqueous solution of sulphuric acid is approximately: (a)0005 (b) 2 (c) 1 (d) The ph of a NaH solution is approximately: (a) 10 (b) 7 (c) 1 (d)14 25 If the dissociation constant of an acid HA is , the ph of a 01 M solution of the acid HA will be approximately: (a) 3 (b) 5 (c) 1 (d) 6 26 The ph of a solution is 50 To this solution sufficient acid is added to decrease the ph to 20 The increase in hydrogen ion concentration is : (a) 1000 times (b) 5/2 (c) 100 times (d) 5 times 27 When the ph of a solution is 2 the hydrogen ion concentration is : (a) M (b) M (c) M (d) M 28 The ph of 1/1000 N KH solution is : (a) (b) 3 (c) 2 (d) Assuming complete dissociation the ph of a 001 M NaH solution is equal to : (a) 20 (b) 140 (c) 120 (d) The ph of the solution obtained by mixing 10 ml of 10 1 N HCl and 10 ml of 10 1 N NaH is: (a) 8 (b) 2 (c) 7 (d) None 31 Which addition would not change the ph of 10 ml of dilute hydrochloric acid : (a) 20 ml of the same dilute hydrochloric acid (b) 5 ml of pure water (c) 10 ml of pure water (d) 10 ml of concentrated hydrochloric acid ml of a solution contains 01 M NH 4 Cl M NH 4 H Which addition would not change the ph of the solution: (a) Adding 1 ml water (b) Adding 5 ml of 01 M NH 4 Cl (c) Adding 5 ml of 01 M NH 4 H (d) Adding 10 ml of 01 M NH 4 Cl 33 At 90 C, pure water has [H 3 + ] = 10 6 mol/litre The value of K w at 90 C is: (a) 10 6 (b) (c) (d) The ph of 10 2 N HCl would be approximately: (a) 1 (b) 15 (c) 2 (d) g NaH present in one litre solution shows the ph : (a) 12 (b) 2 (c) 6 (d) ph of a 10 8 M solution of HCl in water is (a) 8 (b) 8 (c) Between 7 and 8 (d) Between 6 and 7

12 A N S W E R S 1 d 32 a 2 c 33 b 3 c 34 c 4 a 35 a 5 a 36 d 6 d 7 c 8 d 9 b 10 d 11 c 12 b 13 b 14 a 15 b 16 c 17 c 18 c 19 c 20 d 21 b 22 b 23 b 24 b 25 a 26 a 27 b 28 d 29 c 30 c 31 a