Question

How many grams of $KCl$ must be added to $75g$ of water to produce a solution with a molality of $2.25$

• A. 1.257 g
• B. 125.7 g
• C. 12.57 g
• D. 25.14 g

Answer 1

Answer: (C)

Here
$W=75gm$
$M=74.5$
$M=2.25$
$W=?$
As $M=\frac{w\times 1000}{M\times w}$
So $w=\frac{M\times M\times w}{1000}$
$=\frac{2.25\times 74.5\times 75}{1000}=12.57g$