Question

How many grams of $NaOH$ are needed to make 100 g of a 5 % solution?

• A. $2$
• B. $5$
• C. $20$
• D. $40$
• E. $96$

Answer 1

Answer: (B)

$5$

Let $W$ grams of $NaOH$ are needed to make 100 g of a 5 % solution.

$\text{Percentage by mass}=\frac{\text{Mass of NaOH}}{\text{Mass of solution}}\times 100$

$\text{5}=\frac{\text{W g}}{\text{100 g}}\times 100$

$\text{W}=\text{5 g}$