Question

How much $$\mathrm{BaCl}{\phantom{A}}_2\cdot 2\mathrm{H}{\phantom{A}}_2\mathrm{O}$$ and pure water are to be mixed to prepare 50 g of 12.0% (by mass) BaCl₂ solution?

Options

• 40.4 g

• 42.9 g

• 52.7 g

• 50.0 g

Answer 1

42.9 g

Explanation:

w = 12 g of BaCl₂, W = 100 g of solution

For 50 g of solution, w = 6 g of BaCl₂

W = 50 g of solution

$$\therefore \mathrm{w}{\phantom{A}}_{{\mathrm{BaCl}}_2\phantom{.}·\phantom{.}2{\mathrm{H}}_2\mathrm{O}}$$ = ${\displaystyle \left(\frac{6\times 244}{208}\right)}$ g

= 7.038 g

${\displaystyle {\text{w}}_{{\text{H}}_2\text{O}}=(50-7.038)}$ g

= 42.96 g ≈ 42.9 g