Chapter 7, Problem 13CR

To determine

Find the water should be added to solution.

Answer to Problem 13CR

  $30c{m}^3$ water should be added to water for making it $5\%$ salt solution.

Explanation of Solution

Given information:

Quantity of solution $=10c{m}^3$

Percentage of salt in solution is = $20\%$

Now in solution $10c{m}^3$ the quantity of salt is $20\%$ , therefore:

Salt in solution = $\frac{20}{100}\times 10=2c{m}^3$

Water in solution = $\frac{80}{100}\times 10=8c{m}^3$

Let the water added for $5\%$ salt solution be $x$ :

Now adding x litre of water in 8 litres of water to make it 95% water or 5% salt solution:

  $\begin{array}{l}\frac{8+x}{2}=\frac{95}{5}\\ \frac{8+x}{2}=19\\ 8+x=38\\ x=30c{m}^3\end{array}$

  $30c{m}^3$ water should be added to water for making it $5\%$ salt solution.