Question

The active mass of $64gm$ of $HI$ in a two litre flask would be:

• A. $2$
• B. $1$
• C. $5$
• D. $0.25$

Answer 1

Answer: (D)

$0.25$

The expression for the active mass is, $\text{active mass}=\frac{\text{number of moles}}{\text{volume in litres}}==\frac{\frac{mass}{\text{molar mass}}}{\text{volume in litres}}$.
Substitute values in the above expression.
$\text{Active mass}=\frac{\frac{64}{128}}{2}=0.25$.