Question

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

• A. $6\text{gm/l}$
• B. $8\text{gm/l}$
• C. $2.75\text{gm/l}$
• D. $1.5\text{gm/l}$

Answer 1

The correct option is C $2.75\text{gm/l}$

As we know,
$P=\left(\frac{w}{V}\right)\frac{RT}{M}$
$PV=nRT(\because n=\frac{w}{M})$
$\Rightarrow \frac{P_1{M}_1}{d_1{T}_1}=\frac{P_2{M}_2}{d_2{T}_2}(\because M_1=M_2)$

$\text{At STP}(T=273K\text{and}P=1bar)$
$\Rightarrow \frac{2}{5.46\times 300}=\frac{1}{d_2\times 273}$
$\Rightarrow d_2=\frac{5.46\times 300}{2\times 298}=2.75{\text{gm/dm}}^3$