Question

$K_p$ for the reaction $A\rightleftharpoons B$ is 4. If initially only A is present then what will be the partial pressure of B after equilibrium?

<!--td {border: 1px solid #cccccc;}br {mso-data-placement:same-cell;}--> AIIMS 2016

• A. 1
• B. 1.2
• C. 0.8
• D. 0.6

Answer 1

The correct option is C 0.8

For given reaction,
$K_p=K_c$
Assuming that reaction is started with 1 mole of A and at equilibrium x moles of A have reacted,

$K_p=\frac{P_B}{P_A}=4$
$\frac{x}{1-x}=4$
$5x=4x=0.8$