Question

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

• A. 4.05 atm
• B. 2.025 atm
• C. 3.84 atm
• D. 1.92 atm

Answer 1

Answer: (D)

1.92 atm

Answer 2

N2 $\rightarrow$ 2N

at t = 0 $\frac{1.4}{28}$=$\frac{1}{20}$ 0

at t = tf $\frac{1}{20}$ – x 2x

but, x = 30% of $\frac{1}{20}$=$\frac{3}{200}$

Final number of mole = $\frac{1}{20}$ – x + 2x =$\frac{1}{20}$+ x = $\frac{1}{20}$+$\frac{3}{200}$=$\frac{13}{200}$

$\therefore$ P = $\frac{13}{200}$ ×$\frac{0.0821 \times 1800}{5}$ = 1.92 atm.