Question

At certain temperature and a total pressure of ${10}^{5}Pa$, iodine vapours contains $40$% by volume of iodine atoms. $K_p$ for the equilibrium
$I_2\left(g\right)\rightleftharpoons 2I\left(g\right)$

• A. $0.67$
• B. $1.5$
• C. $2.67\times {10}^4$
• D. $9.0\times {10}^4$

Answer 1

The correct option is C $2.67\times {10}^4$

Partial pressure of iodine atoms
$\left(p_1\right)=\frac{40}{100}\times {10}^5=0.40\times {10}^{5}Pa$
Partial pressure of $I_2$
$=\frac{60}{100}\times {10}^{5}Pa=0.60\times {10}^{5}Pa$
$\therefore K_p=\frac{p_I^2}{p_{I_2}}=\frac{{(0.40\times {10}^5)}^2}{0.60\times {10}^5}=2.67\times {10}^4$