Question

Calculate the concentration (in percentage by weight) of a solution obtained by mixing $300 \, g \, 25\%$ by weight solution of $NH_{4}Cl \, $ and $150 \, g \, of \, 40\% \, $ by weight solution of $NH_{4}Cl$ .

Answer 1

Weight of solution $I \, and \, II \, = \, 300 \, + \, 150 \, = \, 450 \, g \, $

Weight of $NH_{4}Cl$ in $I \, solution=\frac{25 \times 300}{100}= \, 75 \, g$

Weight of $NH_{4}Cl$ in $II \, solution$ $=\frac{40 \times 150}{100}=$ $60 \, g$

$\therefore \, \, $ Total weight of $NH_{4}Cl \, = \, 75 \, + \, 60 \, = \, 135 \, g$

$\therefore \, \, \% \, by \, wt. \, of \, mixed \, solution \, =\frac{135}{450}\times \, 100 \, = \, 30\%$