Question

How many grams of solute should be added in $100g$ water to get a solution of density $1.2g/ml$ and strength $5$% (w/v)?

• A. $5g$
• B. $6g$
• C. $4.17g$
• D. $4.35g$

Answer 1

Answer: (C)

$4.17g$

5% (w/v), by definition, means 5 grams of solute per 100 grams of solution.

Since the density is 1.2 g/ml, you can find the volume of 100 grams of solution.

$100gsolution\times \frac{1ml}{1.2g}=83.33ml$.

Hence

$83.33ml\times \frac{5g}{100ml}=4.17g$ solute needed.