CHEMICAL EQUILIBRIUM & SOLIDS

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Thomasina Gregory
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1 CHEMICAL EQUILIBRIUM & SOLIDS MCQ (One option) 1. Equilibrium constant is dependent on temperature. It is because, a. Concentration values change on changing temperature. b. During the reaction heat is either liberated or absorbed. c. Rate constant value change on changing temperature. d. If forward reaction is exothermic, backward reaction is endothermic moles of HI are heated in a litre flask. Equilibrium constant is K 1. K 2 is the equilibrium constant if the flask volume is 2 litres. K 1, & K 2 are related as, a. K 1 =K 2 b. K 1 >K 2 c. K 2 >K 1 d. K 1 =2K 2 3. One of the following is not a reversible reaction. a. 2SO 2 + O 2 2SO 3 b. Zn + H 2 SO 4 ZnSO 4 + H 2 c. CaCO 3 CaO + CO 2 d. CH 3 COOH + NaOH CH 3 COONa + H 2 O

2 4. PCl 5(g) PCl 3(g) + Cl 2(g) Total pressure at equilibrium is 10 atm & partial pressure of Cl 2 is 3 atm. Kp is a. 10/3 b. 9 c. 9/7 d. 9/4 5. The following reaction is started with one mole of A. A B + C + D At equilibrium 50 % of A is dissociated. Kc for the reaction is, a. 1.0 b. 0.5 c d Following reaction on analysis at equilibrium, is found to have 6.4 g of SO 2, 4.8g of O 2 & 4.0 g of SO 3. 2SO 2(g) + O 2(g) 2 SO 3(g) ( Given, at. masses of S & O are 32 & 16) Calculate Kc a. 5/3 b. 1000/(48 x 256) c. (48 x 256)/1000 d. 3/5 7. Two trials are carried out for N 2(g) + 3H 2(g) 2NH 3(g) Trial (1) N 2 & H 2 are taken in the ratio 1:3 by volume Trial (2) N 2 & H 2 are taken in the ratio 3:1 The correct statement on attainment of equilibrium is, a. All the N 2 & H 2 completely react in (1) b. Some amount of N 2 alone will be left out in (2)

3 c. In neither trials complete reaction takes place d. NH 3 is not formed in trial (2) 8. Kc for the dissociation of MA is Calculate [M + ] in 0.1M solution of MA. a b c d N 2(g) + O 2(g) 2NO (g), H = QkJ. At equilibrium, I. Add N2 & remove NO II. Double the volume III. Heat the reaction mixture. The trials which favour forward reaction is/are, a. II b. III & II c. I & III d. I, II & III moles of PCl 3 & 3 moles of Cl 2 are heated. On attaining the equilibrium, PCl 3(g) + Cl 2(g) PCl 5(g) the total number of moles was 5. Calculate the equilibrium constant of the reaction PCl 5(g) PCl 3(g) + Cl 2(g) a. 2.5 b. 1.5 c. 0.5 d. 2.0

4 11. SO 3,SO 2 &O 2 are taken in a 5 litre flask. Equilibrium constant Kc is found to be 50 for the reaction 2SO 2(g) + O 2(g) 2SO 3(g). if [SO 3 ] = [SO 2 ] at equilibrium, calculate the number of moles of O 2 at equilibrium. a b c. 0.2 d The reaction in which the yield of products cannot be increased by the application of pressure. a. 2NO 2(g) N 2 O 4(g) b. N 2(g) + O 2(g) 2NO (g) c. 3O 2(g) 2O 3(g) d. PCl 3(g) + Cl 2(g) PCl 5(g) 13. Equilibrium constant values of a few reactions are given below. Which you think is mostly completed? a. 10 b c. 4.5 x 10 2 d. 3 x PCl 3(g) + Cl 2(g) PCl 5(g) H = +QkJ. At a given temperature, the volume of the reaction vessel is doubled. The true statement regarding the equilibrium constant Kp & degree of dissociation x of PCl 5 a. Both Kp & x change b. Neither Kp nor x change c. Kp changes but not x

5 d. x changes but not Kp mole of H 2 & 0.6 mole of HI are taken. At the equilibrium of the reaction H 2(g) + I 2(g) 2HI (g). Concentration of I 2 is /can a. Not be determined from the data b. 0.4 c. 0 d. 8 e One mole of N 2 & 3 mole of H 2 are taken & heated to attain the equilibrium N 2(g) + 3H 2(g) 2NH 3(g). At equilibrium 0.8 mole of NH 3 is formed & total pressure was 16 atm. Calculate the partial pressure of H 2 at equilibrium. a. 9 atm b. 12 atm c. 4 atm d. 6.2 atm 17. Equilibrium constant of SO 2 + ½ O 2 SO 3 is 2.5. equilibrium constant at same temperature for the reaction 2SO 2 + O 2 SO 3 is a. 0.4 b. 5 c. 0.2 d ½A + 2B 3C. expression for the equilibrium constant of the reverse reaction of the above is

6 a. Kc = [C] 3 [A] ½ [B] 2 b. Kc = [3C] [½A][2B] c. Kc = [½A][2B] [3C] d. Kc = [A] ½ [B] 2 [C] The correct statement for the equilibrium A + B 3C. a. For the addition of every one mole of A, 3 moles of C are formed. b. For the addition of every one mole of A & B, 3 moles of C are formed. c. For every one mole A that reacts 3 moles of C are formed. d. For every 3 moles of C that dissociate, 1.5 mole each of A & B are formed. 20. Following equilibrium is attained by taking 2 moles each of A & B. 2A + B 2C. If 80% of A reacts, the equilibrium constant is a. 160 b c d In case of the reaction 3A + B 3C +QkJ, the conditions under which more of C cannot be obtained. a. Increase the temperature b. Add A or B

7 c. Double the volume of container d. Both a & c 22. Mark the true statements T & false statements F for a reaction if Kp = Kc I. Pressure changes favour forward or backward reaction II. Temperature changes do not shift the equilibrium III. Removal of products favour forward reaction. a. FTT b. FFT c. FTF d. TTF moles of A & 3 moles of B are found at equilibrium of the reaction A B. calculate the concentration of A at new equilibrium on adding one mole of B at the same temperature as before. a. 2.4 b. 1.6 c. 3.6 d The reaction is started with 5 moles of A in a litre flask to attain the equilibrium A B. Equilibrium constant is found to be 4. The degree of dissociation of A is a. 0.2 b c. 0.8 d. 0.08

8 25. 2NH 3(g) N 2(g) + 3H 2(g). The total pressure at equilibrium is 200 atm & partial pressure of NH 3 is 120 atm. Calculate Kp. a x 10-3 b. 100 c. 240 d N 2 & H 2 are made to react by taking 25 moles each. N 2(g) + 3H 2(g) 2NH 3(g) If 5 moles of N 2 reacts at equilibrium, the number of moles of H 2 remaining & NH 3 are formed are, a. 5, 10 b. 10, 5 c. 15, 10 d. 10, mole each of A & B are taken. Equilibrium A + B 2C is attained. Equilibrium constant is 9. The percentage of A remaining un reacted at equilibrium is, a. 60% b. 40% c. 80% d. 30% 100 C 28. H 2 O (l) 1atm pressure H 2 O (g). On applying pressure at equilibrium, the correct statement is, a. More steam is produced b. BP decreases c. Less steam is produced d. No change.

9 29. M+ & A- are accommodated as shown in the figure. A - M + The r M + must be in the range, r A - a b c d The number of balls surrounding a ball of same size in a layer is, a. 3 b. 6 c. 4 d The number of cubic unit cells sharing an atom at the middle of an edge of the cubic unit cell is a. 6 b. 4 c. 3 d Number of systems & spacial arrangements in which solid crystallize. a. 7, 21 b. 14, 7

10 c. 14, 32 d. 7, The wrong statement a. The bond between water molecules in ice is H- bond b. Smallest repetitive unit in a crystal is called unit cell. c. The spacial arrangement in any crystal made of cubic unit cell is same. d. Any unit cell in a given crystal will have identical surrounding. 34. An element crystallizes as FCC. If two atoms of positive faces are missing, number of atoms belong to the unit cell is, a. 4 b. 3 c. 2 d A simple cubic unit cell has 2 more atoms at opposite sides. number of atoms belonging to the unit cell is, a. 1.5 b. 2.0 c. 2.5 d Number of NaCl molecules in a unit cell is, a. 13 b. 8 c. 6

11 d Number of unit cells accommodating 0.585g of NaCl. (given Mol mass of NaCl = 58.5, N A = 6x ) a. 2 x b. 1.5 x c. 3 x d. 6 x M + & A - crystallize as BCC. Its molecular formula is, a. M 2 A b. MA 2 c. MA d. M 3 A The coordination number of Cs in CsCl is, a. 4 b. 6 c. 8 d The number of Na + surrounding Cl - & vice versa is, a. 4, 4 b. 8, 8 c. 6, 8 d. 6, 6

12 CHEMICAL EQUILIBRIUM & SOLIDS KEY 1 c 2 a 3 b 4 d 5 c 6 a 7 c 8 b 9 c 10 d 11 d 12 b 13 c 14 d 15 a 16 a 17 d 18 d 19 c 20 c 21 d 22 b 23 a 24 c 25 d 26 d 27 b 28 c 29 c 30 b 31 b 32 d 33 c 34 b 35 a 36 d 37 b 38 c 39 c 40 d

CHEMISTRY 12 EQUILIBRIUM PROPERTIES & ENTROPY AND ENTHALPY WORKSHEET CHEMISTRY 12 EQUILIBRIUM PROPERTIES WORKSHEET

CHEMISTRY 12 EQUILIBRIUM PROPERTIES & ENTROPY AND ENTHALPY WORKSHEET CHEMISTRY 12 EQUILIBRIUM PROPERTIES WORKSHEET 1) Write six statements that apply to all chemical equilibrium systems. (2 marks) System