Chapter 18, Problem 82A

Interpretation Introduction

Interpretation:

The $pH$ of the solution is to be find out using given concentration of solute in the solvent.

Concept introduction:

pH gives the concentration of hydrogen ion in a solution.

It tells about acidity and basicity of a solution.

It is given by:

$\begin{array}{l}pH=-\log \left[H^{+}\right]\\ pOH=-\log \left[O{H}^{-}\right]\\ pH+pOH=14\\ \left[H^{+}\right]isconcentationofhydrogenions\\ \left[O{H}^{-}\right]isconcentationofhydroxylions\end{array}$

Answer to Problem 82A

$pH=0.523$

Explanation of Solution

Given data:

$\begin{array}{l}{V}_{HCl}=5mL\\ =0.005L\\ Molarity=6M\\ V_{water}=95mL\end{array}$

$\begin{array}{c}NumberofmolesofHCl=6\times 0.005\\ =0.03mol\end{array}$

Volume of solution = $0.1L$

$\begin{array}{c}\left[HCl\right]=\frac{0.03mol}{0.1L}\\ =0.3M\end{array}$

$HCl$ dissociates as:

$HCl\to H^{+}+C{l}^{-}$

Thus, $0.3M$

$HCl$ will produce $0.3M$

$H^{+}$

Therefore,

$\left[H^{+}\right]=0.3M$

$\begin{array}{c}pH=-\log (0.3)\\ =0.523\end{array}$

Conclusion

Thus,

$pHofHCl=0.523$