The value of their solubility unit (K - R-Shiksha Trust

The value of their solubility unit (K

The value of their solubility unit (K

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 > Lewis acid PF3 > electron rich > Lewis base CO > having lone pair of electron > Lewis base F – > unshared pair of electron > lewis base

Matter 10. Brand new aqueous possibilities out of sodium formate, anilinium chloride https://datingranking.net/escort-directory/macon/ and you may potassium cyanide are correspondingly (a) acid, acidic, very first (b) basic, acidic, very first (c) first, natural, earliest (d) not one ones Address: (b) very first, acidic, very first

Matter 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 + ] =

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