Ncert Exercises & Solutions

G i v e n,

d_{1} = 5.46 g / d m^{3}

p_{1} = 2 b a r

T_{1} = 27 ° C = (27 + 273) K = 300 K

p_{2} = 1 b a r

T_{2} = 273 K

d_{2} = ?

The density

(d_{2})

of the gas at STP can be calculated using the equation,

d = \frac{M p}{R T}

\Rightarrow \frac{d_{1}}{d_{2}} = \frac{\frac{M p_{1}}{R T_{1}}}{\frac{M p_{2}}{R T_{2}}}

\Rightarrow \frac{d_{1}}{d_{2}} = \frac{p_{1} T_{2}}{p_{2} T_{1}}

\Rightarrow d_{2} = \frac{p_{2} T_{1} d_{1}}{p_{1} T_{2}}

= \frac{1 \times 300 \times 5.46}{2 \times 273}

= 3 g d m^{- 3}

Hence, the density of the gas at STP will be 3 g

d m^{- 3}