NEET Solved Paper 2016 Question 10

Question: MY and $ N{Y_3}, $ two nearly insoluble salts, have the same $ K _{sp} $ values of $ 6.2\times 10^{13} $ at room temperature. Which statement would be true in regard to MY and $ N{Y_3} $ ?

Options:

A) The molar solubilities of MY and $ N{Y_3} $ in water are identical.

B) The molar solubility of MY in water is less than that of $ N{Y_3} $

C) The salts MY and $ N{Y_3} $ are more soluble in 0.5 M KY than in pure water.

D) The addition of the salt of KY to solution of MY and $ N{Y_3} $ will have no effect on their solubilities.

Show Answer

Answer:

Correct Answer: B

Solution:

$ MY\to K _{sp}=s^{2}=6.2\times {10^{-13}} $ $ s=\sqrt{6.2\times {10^{-13}}} $ $ s=7.87\times {10^{-7}},mol,{L^{-1}} $ $ NY _3\to K _{sp}=27,s^{4}=6.2\times {10^{-13}} $ $ s={{( \frac{6.2\times {10^{-13}}}{27} )}^{1/4}} $ $ s=3.89\times {10^{-4}},mol,{L^{-1}} $

$ \therefore $ molar solubility of $ NY _3 $ is more than MY in water.