Question

How many gram of $NaCl$ is required to make $200$ mL aqueous solution of $5\%\left(w/v\right)NaCl$.

Answer 1

We know that,

%$\frac{W}{V}=\frac{\text{Mass of solute(g)}\times 100}{\text{Volume in mL}}$

Let x be the mass of solute,

$⟹5=\frac{x}{200}\times 100$

$⟹x=10g$