Chemical And Ionic Equilibrium Result Question 45
45. (a) The degree of dissociation is $0.4$ at $400$ K and $1.0$ atm for the gaseous reaction $\mathrm{PCl}_5 \rightleftharpoons \mathrm{PCl}_3+\mathrm{Cl}_2$. Assuming ideal behaviour of all the gases, calculate the density of equilibrium mixture at $400$ K and $1.0$ atm (relative atomic mass of $\mathrm{P}=31.0$ and $\mathrm{Cl}=35.5$ ).
(b) Given, $\left[\mathrm{Ag}\left(\mathrm{NH}_3\right)_2^{+}\right] \rightleftharpoons \mathrm{Ag}^{+}+2 \mathrm{NH}_3$,
$\begin{aligned} K_c & =6.2 \times 10^{-8} \text { and } K_{\text {sp }} \text { of } \mathrm{AgCl} \\ & =1.8 \times 10^{-10} \text { at } 298 \mathrm{~K} . \end{aligned}$
If ammonia is added to a water solution containing excess of $\mathrm{AgCl}(s)$, calculate the concentration of the complex in $1.0$ M aqueous ammonia.
$(1998,3 M+5 M)$
Show Answer
Answer:
Correct Answer: 45. ( $\mathrm{SO} _4^{2-}$ )
Solution:
Average molar mass $=\frac{208.5}{1.4}=148.9$
$\rho(\text { density })=\frac{p M}{R T}=\frac{1 \times 148.9}{0.082 \times 400}=4.54 \mathrm{~g} / \mathrm{L}$
(b)
$\begin{aligned} & K=\frac{K_{\text {sp }}}{K_c}=2.9 \times 10^{-3}=\left(\frac{x}{1- x}\right)^2 \\ & x=0.049 \mathrm{M} \\ \end{aligned}$
BETA
