Chapter 14, Problem 78A

Interpretation Introduction

Interpretation:

Required volume of dilutedH₃PO₄ solution is to be calculated.

Concept introduction:

The equation for dilution is

$\begin{array}{l} M_1{V}_1=M_2{V}_2\hfill \\ Stocksolution=Dilutedsolution\hfill \end{array}$

Concentrated solutions of known molarities are known as stock solution.

Where,

M₁ = molarity of the stock solution V₁ = volume of stock solution

M₂ = molarity of the diluted solution V₂ = volume of diluted solution

Answer to Problem 78A

158.33 mLof 3.0 M phosphoric acid solutioncan bemadefrom95 mL 5.0 M $H_{3}P{O}_4$ solution.

Explanation of Solution

Given information:

Molarity of the stock $H_{3}P{O}_4$ solution $M_1=5.0M$.

Volume of the stock $H_{3}P{O}_4$ solution $V_1=95mL$.

Molarity of the diluted $H_{3}P{O}_4$ solution $M_2=3.0M$.

Write the expression for dilution.

$\begin{array}{l} M_1{V}_1=M_2{V}_2\hfill \\ Stocksolution=Dilutedsolution\hfill \end{array}$

Volume of 3.0 M dilutedH₃PO₄ solution = V₂

$\begin{array}{l}{V}_2=\frac{M_1{V}_1}{M_2}\\ V_2=\frac{5.0M\times 95mL}{3.0M}=158.33mL\end{array}$

Volume of 3.0 M dilutedH₃PO₄ solution = 158.33 mL