Some Basic Concepts of Chemistry - Result Question 13
21. Mixture $X=0.02 \mathrm{~mole}$ of $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_5 \mathrm{SO}_4\right] \mathrm{Br}$ and 0.02 mole of $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_5 \mathrm{Br}\right] \mathrm{SO}_4$ was prepared in 2 L solution.
1 L of mixture $X+$ excess of $\mathrm{AgNO}_3$ solution $\longrightarrow Y$
1 L of mixture $X+$ excess of $\mathrm{BaCl}_2$ solution $\longrightarrow Z$
Number of moles of $Y$ and $Z$ are
(2003, 1M)
(a) $0.01,0.01$
(b) $0.02,0.01$
(c) $0.01,0.02$
(d) $0.02,0.02$
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Answer:
Correct Answer: 21. (a)
Solution:
- 1.0 L of mixture $X$ contain 0.01 mole of each $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_5 \mathrm{SO}_4\right] \mathrm{Br}$
and $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_5 \mathrm{Br}\right] \mathrm{SO}_4$. Also, with $\mathrm{AgNO}_3$, only
$\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_5 \mathrm{SO}_4\right] \mathrm{Br}$ reacts to give AgBr precipitate as
$\underset{1.0 \text { mol }}{\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_5 \mathrm{SO}_4\right] \mathrm{Br}}+\underset{\text { Excess }}{\mathrm{AgNO}_3} \rightarrow\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_5 \mathrm{SO}_4\right] \mathrm{NO}_3+\underset{1.0 \mathrm{~mol}}{\mathrm{AgBr}}$
With $\mathrm{BaCl}_2$, only $\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_5 \mathrm{Br}\right] \mathrm{SO}_4$ reacts giving $\mathrm{BaSO}_4$ precipitate as
$\underset{1.0 \mathrm{~mol}}{\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_5 \mathrm{Br}\right] \mathrm{SO}_4}+\underset{\text { Excess }}{\mathrm{BaCl}_2} \rightarrow\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_5 \mathrm{Br}\right] \mathrm{Cl}_2+\underset{1 \mathrm{~mol}}{\mathrm{BaSO}_4}$
Hence, moles of $Y$ and $Z$ are 0.01 each.
BETA
