Chapter 15.3, Problem 4RQ

Interpretation Introduction

Interpretation: The critical information necessary to find the volume of the substance needs to be determined.

Concept introduction: In an acid−base reaction when number of moles of $H^{+}$ is exactly equal to the number of moles of $O{H}^{-}$ it is called point of neutralization and the reaction is called neutralization reaction.

Answer to Problem 4RQ

Concentration of the substance whose volume is being determined is needed.

Explanation of Solution

At neutralization point of a reaction,

  $\begin{array}{c}\text{number of moles of acid}=\text{number of moles of of base}\\ M_1{V}_1=M_2{V}_2\end{array}$

Where,

  $M_1=\text{concentration of acid}\text{.}$

  $V_1=\text{ volume of the acid}\text{.}$

  $M_2=\text{concentration of base}\text{.}$

  $V_2=\text{ volume of the base}\text{.}$

Say we need to determine the volume of acid. First step is to determine the moles of base present in solution initially.

Moles of base $=M_2\times V_2=n(\text{say)}$ . If we know the concentration of the acid then from $M_1{V}_1=M_2{V}_2$ equation we can easily calculate the volume of acid ( $V_1$ ) needed in neutralization reaction.

Conclusion

Concentration of the substance whose volume is being determined is needed.