Chapter 16, Problem 61A

Interpretation Introduction

Interpretation:

The volume of one drop and hydrogen ion concentration in the given solution is to be calculated.

Concept introduction:

An acid is a substance which gives hydrogen ions in aqueous solution.

A strong acid is completely dissociated.

Answer to Problem 61A

Volume of one drop $=0.05mL$

  $\left[H^{+}\right]=2\times {10}^{-1}M$

Hydrogen ion concentration is increased by $factor=2\times {10}^6$.

Explanation of Solution

  $\begin{array}{l}20dropsareequivalentto1mL\\ \therefore Volumeof1drop=\frac{1}{20}\\ =0.05mL\end{array}$

  $\left[HCl\right]=0.200M$

Strong acid is completely dissociated. So,

  $\begin{array}{l}\left[H^{+}\right]=0.200M\\ =2\times {10}^{-1}M\end{array}$

  $\left[H^{+}\right]of1mLwater=1\times {10}^{-7}M$

  $\begin{array}{c}factor=\frac{2\times {10}^{-1}}{1\times {10}^{-7}}\\ =2\times {10}^6\end{array}$

Conclusion

Thus, on adding small amount of acid in water, there is a large increase in hydrogen ion concentration.