Question step three. The solubility of BaSO_cuatro in water is dos.42 x ten -3 gL -1 at 298K. _sp) will be ………………….. (Given molar mass of BaSO₄ = 233g mol -1 ) (a) 1.08 x 10 -14 mol 2 L 2 (b) 1.08 x 10 -12 mol 2 L 2 (c) 1.08 x 10 -10 mol 2 L 2 (d) 1.08 x 10 -8 mol 2 L -2 Answer: (c) 1.08 x 10 -10 mol 2 L 2 BaSO₄ \(\rightleftharpoons\) Ba 2+ + SO₄ 2- K_sp = (s) (s) K_sp = (s) 2

Question 4. pH of a saturated solution of Ca(OH)₂ is 9. The Solubility product (K) of Ca(OH)₂ ……………….. (a) 0.5 x 10 -15 (b) 0.25 x 10 -10 (c) 0.125 x 10 -15 (d) 0.5 x 10 -10 Answer: (a) 0.5 x 10 -15 Ca(OH)₂ \(\rightleftharpoons\) Ca 2+ + 2OH – Given that pH = 9 pOH = 14 – 9 = 5 [p0K = – 1og₁₀[OH – ]] [OH – ] = 10 -pOH [OH – ] =10 -5 M K_sp = [Ca 2+ ] [OH – ] 2

Question 5. Conjugate base for bronsted acids H₂O and HF are ……………… (a) OH – and H₂FH + , respectively (b) H₃O + and F – , respectively (c) OH – and F – , respectively (d) H₃O + and H₂F + , respectively Answer: (c) OH – and F – , respectively

Question 6. Which will make basic buffer? (a) 50 mL of 0.1M NaOH + 25mL of 01M CH₃COOH (b) 100 mL of 0.1M CH₃COOH + 100 mL of 0.1M NH₄OH (c) 100 mL of 0.1M HCI + 200 mL of 0.1M NH₄OH (d) 100 mL of 0.1M HCI + 100 mL of O.1 M NaOH Answer: (c) 100 mL of 0.1M HCI + 200 mL of 0.1M NH₄OH Basic buffer is the solution which has weak base and its salt

Answer: (b) PF

Question 7. Which of the following fluro – compounds is most likely to behave as a Lewis base? (a) BF₃ (b) PF₃ (c) CF₄ (d) SiF_{4 3} BF₃ > electron deficient > Lewis acid PF₃ > electron rich > Lewis base CF₄ > neutral > neither lewis acid nor base SiF₄ > neutral > neither lewis acid nor base

Which of these is not likely to act as lewis base? (a) BF₃ (b) PF₃ (c) CO (d) F – Answer: (a) BF₃ BF₃ > electron deficient > Lewis Rockford escort service acid PF₃ > electron rich > Lewis base CO > having lone pair of electron > Lewis base F – > unshared pair of electron > lewis base

Concern ten. The latest aqueous selection off sodium formate, anilinium chloride and you may potassium cyanide try respectively (a) acidic, acid, basic (b) very first, acid, earliest (c) first, natural, basic (d) not one of them Respond to: (b) earliest, acid, basic

Question 8

Question 11. The percentage of pyridine (C₅H₅N) that forms pyridinium ion (C₅H₅NH) in a 0.10M aqueous pyridine solution (Kb for C₅H₅N = 1.7 x 10 -9 ) iS …………….. (a) 0.006% (b) 0.013% (c) 0.77% (d) 1.6% Answer: (b) 0.013%

Question 12. Equal volumes of three acid solutions of pH 1,2 and 3 are mixed in a vessel. What will be the H + ion concentration in the mixture? (a) 37 x 10 -2 (b) 10 -6 (c) 0.111 (d) none of these Answer: (a) 3.7 x 10 -2 pH = – log₁₀ [H + ] [H + ] = 10 -pH Let the volume be x mL V₁M₁ + V₂M₂ + V₃M₃ = VM x mL of 10 -1 M + x mL of 10 -2 M + x mL of 10 -3 M = 3 x mL of [H + ] = 3 x mL of [H + ] [H + ] =