Question

A vessel of volume $5$ liter contains $1.4g$ of nitrogen at a temperature $1800K$. The pressure of the gas if $30$% of its molecules are dissociated into atoms at this temperature is :

• A. $4.05atm$
• B. $2.0245atm$
• C. $3.84atm$
• D. $1.92atm$

Answer 1

The correct option is A $4.05atm$

Reaction involved, dissociation of nitrogen gas

$N_2\rightleftharpoons 2N$

mass of nitrogen $=1.4g$

$\Rightarrow moles=1.4/28=0.05$

moles after dissociation of $N_2=1.05\times \frac{70}{100}$

and after dissociation of $2N=0.05\times 2\times \frac{30}{100}$

total moles involved $=0.065$

applying ideal gas equation $(PV=nRT)$

$P=\frac{\left(nRT\right)}{V}$

$=1.92atm$