Question

For reaction, $2 NOCl _{( g )} \rightleftharpoons 2 NO _{(g)}+ Cl _{2}(g), K_{C}$ at $427^{\circ} C$ is $3 \times 10^{-6} L \cdot mol ^{-1} .$ The value of $K_{p}$ is nearly

• A. $750 \times 10^{-5}$
• B. $2.50 \times 10^{-5}$
• C. $2.50 \times 10^{-4}$
• D. $1.75 \times 10^{-4} .$

Answer 1

Answer: (D)

$K_{p}=K_{c}(R T)^{\Delta n}$
$\Delta n=$ change in gaseous moles.
For the reaction
$2 NOCl (g) \rightleftharpoons2 NO (g)+ Cl _{2}(g)$
$K_{c}=3 \times 10^{-6} L mol ^{-1}, R=0.0821\, L\, atm / K mol$
$\Delta n=3-2=1$
$T=427+273=700\, K$
$K_{p}=3 \times 10^{-6} \times(0.0821 \times 700)^{1}$
$=1.72 \times 10^{-4}$