Chapter 7.7, Problem 2P

To determine

To Find: The quantity of water to be dissolved in acid solution.

Answer to Problem 2P

  $160ml$

Explanation of Solution

Given:

  $\begin{array}{l}\text{Quantity of solution: }40ml\\ \text{Amount of acid in solution: }50\%\\ \text{Amount of acid in new solution: }10\%\end{array}$

Formula Used:

  $\text{Total amount }\times \text{ \% acid = Amount of acid}$

Calculation:

  $\begin{array}{l}\text{Let the number of water in solution be }x\\ \text{Amount of acid from the original solution: }40\times 0.50=20\\ \text{Amount of acid from water: }x\times 0=0\\ \text{Amount of acid in new solution: }0.10\left(40+x\right)\\ 20=0.10\left(40+x\right)\\ \Rightarrow 20=4+0.1x\\ \Rightarrow x=\frac{16}{0.1}\\ \Rightarrow x=160\end{array}$

	Total amount X	%acid	= Amount of Acid
Original Solution	40	0.50	20
Water Added	160	0	0
New Solution	200	10	20

Conclusion:

Thus the amount of water to be mixed be $160ml$