Question

The density of a gas at ${27}^{o}C$ and 1 atm is 'd'. Pressure remaining constant, the temperature at which its density becomes 0.75 d is :

• A. ${20}^{o}C$
• B. ${30}^{o}C$
• C. 400K
• D. 300K

Answer 1

Answer: (C)

400K

Density of an ideal gas is given by, $d=\frac{PM}{RT}$, where M is the molar mass of the gas.

Since pressure is constant, $d_1{T}_1=d_2{T}_2$

Here, $d_1=d$

$T_1=300K$

$d_2=0.75d$

$T_2=?$

Putting all the values, we get,

$d\times 300=0.75d\times T_2$

$T_2=400K$.

Therefore, the option is C.