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 ?

• A. 1.2
• B. 0.8
• C. 0.6
• D. 1

Answer 1

Answer: (B)

0.8

Answer 2

Assuming that reaction is started with 1 mol of A and at equilibrium x moles of A have reacted, $\quad\quad\quad\quad\quad\quad\quad \quad A\quad\quad\longrightarrow\quad \quad B$ Initially$\quad\quad\quad\quad\quad$1 mol $\quad\quad\quad\quad\quad0$ At equibrium$\quad\quad$ 1-x mol$\quad\quad\quad\quad$x mol $K_{p}=\frac{P_{B}}{P_{A}}=4 \Rightarrow \frac{x}{1-x}=4 \Rightarrow x =0.8$