Question

$N{H}_{4}COON{H}_2\left(s\right)\rightleftharpoons 2N{H}_3\left(g\right)+C{O}_2\left(g\right)$. If equilibrium pressure is $3$ atm for the given reaction, $K_p$ for the reaction is:

• A. $4$
• B. $27$
• C. $4/27$
• D. $1/27$

Answer 1

Answer: (A)

$4$

$N{H}_{4}COON{H}_2\left(S\right)\to 2N{H}_3\left(g\right)+C{O}_2\left(g\right)$

When temperature and volume are constant and the number of moles of a gas is proportional to its partial pressure

For two moles of $N{H}_3\to$ partial pressure $=2p$

For one mole of $C{O}_2\to$ partial pressure $=p$

Hence the total pressure $=2p+p=3$ (since $p=1atm$)

$K_p={\left(2p\right)}^2\left(p\right)=4p^3$

$=4{\left(1\right)}^3=4$