Question

Density of a gas is found to be $5.46\text{g/dm}{}^3$ $\text{at 27}{}^{\circ }\text{C}$ and $\text{2 atm}$ pressure. What will be its density at STP?

• A. $3\text{g/dm}{}^3$
• B. $4\text{g/dm}{}^3$
• C. $5\text{g/dm}{}^3$
• D. $6\text{g/dm}{}^3$

Answer 1

The correct option is A $3\text{g/dm}{}^3$

Given:
$d_1=5.46\text{g/dm}{}^3$
$T_1=300K$
$P_1=2\text{atm}$
$T_2=273K$
$P_2=1\text{atm}$
$d_2=?$
We have studied a relation between molar mass and density as : $M=\frac{dRT}{P}$
So here since molar mass is not changing
$\Rightarrow \frac{d_{1}R{T}_1}{P_1}=\frac{d_{2}R{T}_2}{P_2}$
$\Rightarrow \frac{5.46\times 300}{2}=\frac{d_2\times 273}{1}$
$\Rightarrow d_2=3\text{g/dm}{}^3$