Question

The degree of dissociation is $0.4$ at $400$K and $1.0$ atm for the gaseous reaction $PC{l}_5\rightleftharpoons PC{l}_3+C{l}_2$. Assuming ideal behaviour of all the gases, calculate the density of equilibrium mixture at $400$K and $1.0$ atm.

(Relative atomic mass of $P=31.0$ and $Cl=35.5$)

• A. 1.3
• B. 67
• C. 4.53
• D. None of the above

Answer 1

The correct option is D None of the above

$PC{l}_5\rightleftharpoons PC{l}_3+C{l}_2$

$100$

$1.040.40.5$

Total moles $\to 1-0.4+0.4+0.4$

$=1.4$

$HSO$ normal mol wt of $PC{l}_5/$

exp mol. wt f $PC{l}_5$

$\Rightarrow 1+\alpha =0.4$

Or

208.5/ exp. mol. wt of $PC{l}_5=1.4$

$\therefore$ Exp. mol.wt. of $PC{l}_5$ or m. wt. of mixture

$\Rightarrow \frac{208.5}{1.4}$

Now using, $PV=\frac{W}{M}$ RT for mixture

$d=\frac{W}{V}=\frac{PM}{RT}=\frac{1\times 208.5}{1.4\times 0.082\times 400}=4.53g/lt.$