Question 3. The solubility of BaSOcuatro 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- Ksp = (s) (s) Ksp = (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 Ksp = [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) SiF4 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 > Independence escort girls Lewis acid PF3 > electron rich > Lewis base CO > having lone pair of electron > Lewis base F – > unshared pair of electron > lewis base
Concern ten. Brand new aqueous solutions from salt formate, anilinium chloride and you can potassium cyanide are correspondingly (a) acidic, acidic, first (b) earliest, acidic, very first (c) earliest, natural, basic (d) none ones Answer: (b) basic, acidic, basic
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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 + ] =
