Question

At ${27}^{o}C$ and 1 atm pressure, density of a gas is $d$. At constant P, what will be the temperature if its density is 0.75$d$?

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

Answer 1

Answer: (C)

$400K$

From gas equation,

$\frac{P_1}{d_1{T}_2}=\frac{P_2}{d_2{T}_2}$

$P_1=P_2=1atm.$

$d_1=d;$

$d_2=0.75d$

$T_1={27}^{o}C$

$=27+273$

$=300K$

$T_2=T=?$

$\frac{1}{d\times 300}=\frac{1}{T\times 0.75d}$

$T=\frac{300}{0.75}$

$=400K$

Hence, option (C) is the correct answer.