Chapter 16, Problem 59A

(a)

Interpretation Introduction

Interpretation:

The more basic solution is to be identified.

Concept introduction:

According to Arrhenius,

Acid is a substance which gives hydrogen ion and Base is a substance which gives hydroxyl ions in aqueous solution.

  $If\left[H^{+}\right]=\left[O{H}^{-}\right]$or $pH=pOH$, the solution is neutral.

  $If\left[H^{+}\right]<\left[O{H}^{-}\right]$ or $pH>7$ , the solution is basic.

  $If\left[H^{+}\right]>\left[O{H}^{-}\right]$ or $pH<7$, the solution is acidic.

Answer to Problem 59A

The solution with $\left[O{H}^{-}\right](solution-II)=0.0000032M$ is more basic.

Explanation of Solution

  $K_w=\left[H^{+}\right]\times \left[O{H}^{-}\right]$

Given data for solution-I:

  $\begin{array}{c}\left[H^{+}\right]=0.000013\\ =1.3\times {10}^{-5}M\end{array}$

Therefore,

  $\begin{array}{c}\left[O{H}^{-}\right]=\frac{K_w}{\left[H^{+}\right]}\\ =\frac{1\times {10}^{-14}}{1.3\times {10}^{-5}}\\ =7.7\times {10}^{-10}M\end{array}$

  $\left[O{H}^{-}\right](solution-I)=7.7\times {10}^{-10}M$

  $\begin{array}{c}\left[O{H}^{-}\right](solution-II)=0.0000032\\ =3.2\times {10}^{-6}M\end{array}$

Hydroxyl ion concentration of second solution is more than first solution. So, second solution is more basic.

(b)

Interpretation Introduction

Interpretation:

The more basic solution is to be identified.

Concept introduction:

According to Arrhenius,

Acid is a substance which gives hydrogen ion and Base is a substance which gives hydroxyl ions in aqueous solution.

  $If\left[H^{+}\right]=\left[O{H}^{-}\right]$or $pH=pOH$, the solution is neutral.

  $If\left[H^{+}\right]<\left[O{H}^{-}\right]$ or $pH>7$ , the solution is basic.

  $If\left[H^{+}\right]>\left[O{H}^{-}\right]$ or $pH<7$, the solution is acidic.

Answer to Problem 59A

The solution with $\left[O{H}^{-}\right](solution-II)=1.54\times {10}^{-8}M$ is more basic.

Explanation of Solution

  $K_w=\left[H^{+}\right]\times \left[O{H}^{-}\right]$

Given data for solution-I:

  $\left[H^{+}\right]=1.03\times {10}^{-6}M$

Therefore,

  $\begin{array}{c}\left[O{H}^{-}\right]=\frac{K_w}{\left[H^{+}\right]}\\ =\frac{1\times {10}^{-14}}{1.03\times {10}^{-6}}\\ =9.7\times {10}^{-9}M\end{array}$

  $\left[O{H}^{-}\right](solution-I)=9.7\times {10}^{-9}M$

  $\left[O{H}^{-}\right](solution-II)=1.54\times {10}^{-8}M$

Hydroxyl ion concentration of second solution is more than first solution. So, second solution is more basic.

(c)

Interpretation Introduction

Interpretation:

The more basic solution is to be identified.

Concept introduction:

According to Arrhenius,

Acid is a substance which gives hydrogen ion and Base is a substance which gives hydroxyl ions in aqueous solution.

  $If\left[H^{+}\right]=\left[O{H}^{-}\right]$or $pH=pOH$, the solution is neutral.

  $If\left[H^{+}\right]<\left[O{H}^{-}\right]$ or $pH>7$ , the solution is basic.

  $If\left[H^{+}\right]>\left[O{H}^{-}\right]$ or $pH<7$, the solution is acidic.

Answer to Problem 59A

Solution-I is basic and II is neutral.

Explanation of Solution

  $\left[O{H}^{-}\right](solution-I)=4.02\times {10}^{-7}M$

  $\begin{array}{c}\left[O{H}^{-}\right](solution-II)=0.0000001\\ =1\times {10}^{-7}M\end{array}$

Hydroxyl ion concentration of second solution is less than first solution. So, first solution is more basic.

In actual, solution-I is basic in nature and solution-II is neutral.