Question

At. N.T.P. 28 g of Nitrogen occupies 22.4 litres. What is the mass of 5.6 litres of Nitrogen at 38 cm Hg pressure and ${273}^{0}C$ temperature is then

• A. 1.87 g
• B. 48 g
• C. 1.75 g
• D. 1.5 g

Answer 1

The correct option is A 1.87 g

Given,

At, NTP (293 K, 76 cm Hg): Volume,$V=22.4L$ ,Number of mole, $n_1=1mole$

$273{}^{o}C=546K$

At (38 cm, 546 K): Volume $V=5.6L$

From ideal gas equation.

$PV=nRT$

$\frac{P_1{V}_1}{P_1{V}_2}=\frac{n_{1}R{T}_1}{n_{2}R{T}_2}$

$\Rightarrow \frac{76\times 22.4}{38\times 5.6}=\frac{1\times R\times 293}{n_{2}R\times 546}$

$\Rightarrow n_2=0.67mole$

$1mole{N}_2=28g$

$0.067mole{N}_2=28\times 0.067=1.87g$

Hence, mass of nitrogen is $1.87g$