Question bank/JEE Main/Chemistry

JEE MainChemistryModeratePhysical Chemistry

On mixing equal volumes of 0.1 M AgNO3 & 0.8 M KCN solutions,
what of original Ag+ is in the form of free Ag+ ions ? Given: Kd of

[Ag(CN)2]- = 10-18. Report your answer after multiplying it by 4.5 ×

1016. (Assume no hydrolysis of any ion)

Show answer and solution
10−18=[Ag+]free(0.3)2(0.05)⇒[Ag+]free=59×10−18M10^{- 18} = \frac{\left\lbrack {Ag}^{+} \right\rbrack_{free}(0.3)^{2}}{(0.05)} \Rightarrow \left\lbrack {Ag}^{+} \right\rbrack_{free} = \frac{5}{9} \times 10^{- 18}M
% of Ag+(Ag+%)=59×10−180.05×100×4.5×1016=50%\%\ of\ {Ag}^{+}\left( {Ag}^{+}\% \right) = \frac{\frac{5}{9} \times 10^{- 18}}{0.05} \times 100 \times 4.5 \times 10^{16} = 50\%

Source: Grass-G / CH-23 Chemistry Paper 31 Dec. FST.docx

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