Chemical And Ionic Equilibrium Result Question 24
24. When equal volumes of the following solutions are mixed, precipitation of $\mathrm{AgCl}\left(K_{\text {sp }}=1.8 \times 10^{-10}\right)$ will occur only with
(1988, 1M)
(a) $10^{-4} \mathrm{M}\left(\mathrm{Ag}^{+}\right)$and $10^{-4} \mathrm{M}\left(\mathrm{Cl}^{-}\right)$
(b) $10^{-5} \mathrm{M}\left(\mathrm{Ag}^{+}\right)$and $10^{-5} \mathrm{M}\left(\mathrm{Cl}^{-}\right)$
(c) $10^{-6} \mathrm{M}\left(\mathrm{Ag}^{+}\right)$and $10^{-6} \mathrm{M}\left(\mathrm{Cl}^{-}\right)$
(d) $10^{-10} \mathrm{M}\left(\mathrm{Ag}^{+}\right)$and $10^{-10} \mathrm{M}\left(\mathrm{Cl}^{-}\right)$
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Answer:
Correct Answer: 24. ( a )
Solution:
- For precipitation to occur, $K_{\text {sp }} > Q_{\text {sp }}$.
$Q_{\mathrm{sp}}=\left(\frac{10^{-4}}{2}\right)\left(\frac{10^{-4}}{2}\right)=2.5 \times 10^{-9} > K_{\text{sp}}$
Hence, precipitate will be formed in this case. In all other cases, $Q_{\mathrm{sp}} < K_{\mathrm{sp}}$ and no precipitation will occur.
BETA
