Question

The ionization constant of chloroacetic acid is 1.35 × $10^{-3}$. What will be the pH of 0.1 M acid and its 0.1M sodium salt solution ?

Answer 1

The ionization reaction of “chloroacetic acid” is as follows.

              ${ CH }_{ 2 }ClCOOH\quad \leftrightarrow \quad C{ H }_{ 2 }ClCO{ O }^{ - }\quad +\quad { H }^{ + }$

Let's calculate the concentration of hydrogen.

              $[{ H }^{ + }]\quad =\quad \sqrt { { K }_{ a }C }$

              $=\quad \sqrt { 1.35\quad \times \quad { 10 }^{ -3 }\quad \times \quad 0.1 }$

              $[{ H }^{ + }]\quad =\quad 1.16\quad \times \quad 1{ 0 }^{ -2 }$

Let's calculate the pH by using hydrogen ion concentration.

              $pH\quad =\quad -log[{ H }^{ + }]$

              $=\quad -log\quad (1.16\quad \times { 10 }^{ -2 })$

              $pH\quad =\quad 1.94$

Sodium salt of chloroacetic acid is a strong base NaOH and weak acid chloroacetic acid.

Hence,

              $pH\quad =\quad - \frac { 1 }{ 2 } [\quad log\quad { K }_{ w }\quad +\quad log\quad { K }_{ a }\quad -\quad log\quad c]$

              $=\quad -\quad \frac { 1 }{ 2 } [-log\quad { K }_{ w }\quad +\quad log\quad { K }_{ a }\quad -\quad log\quad c]$

              $=\quad [+14\quad -\quad log\quad 1.35\quad \times \quad { 10 }^{ -3 }]$

              $pH\quad =\quad \frac { 14\quad +\quad 2.87\quad -1 }{ 2 } \quad 7.94$

Therefore, pH of the solution is 7.94.

Answer 2

HEYA MATE.....

THE pH of the Solution is .......
7.94

I HOPE IT IS HELPFUL....☺✌☺