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

Asked by Pragya Singh | 1 year ago |  135

##### Solution :-

The Ka for chloroacetic acid (ClCH2COOH) is $$1.35\times 10^{-3}$$.

$$\Rightarrow K_{a} = c\alpha ^{2}$$

$$\alpha = \sqrt{\dfrac{K_{a}}{c}}$$

$$= \sqrt{\dfrac{1.35\times 10^{-3}}{0.1}}$$​​; (given concentration = 0.1M)

$$\alpha = \sqrt{1.35\times 10^{-2}}$$

= 0.116

$$[H^{+}] = c\alpha = 0.1×0.116 = 0.0116$$

$$pH = -\log [H^{+}] = 1.94$$

ClCH2COONa is a salt of strong base i.e. NaOH, and weak acid i.e. ClCH2COOH

$$ClCH_{2}COO^{-} + H_{2}O$$

$$\leftrightarrow ClCH_{2}COOH + OH^{-}$$

$$K_{h} = \dfrac{[ClCH_{2}COO][OH^{-}]}{[ClCH_{2}COO^{-}]}$$

Now, $$K_{h} = \dfrac{K_{w}}{K_{a}}$$

$$K_{h} = \dfrac{10^{-14}}{1.35\times 10^{-3}}$$

$$= 0.740\times 10^{-11}$$

Also, $$K_{h} = \dfrac{y^2}{0.1}\Rightarrow \; 0.740\times 10^{-11}$$

$$= \dfrac{y^2}{0.1}\Rightarrow \; 0.0740\times 10^{-11} = y^2$$

y =$$0.86\times 10^{-6}$$

$$[OH^{-}] = 0.86\times 10^{-6}$$

$$[H^{+}] =\dfrac{K_{w}}{0.86\times 10^{-6}}$$

$$Kw​​ =\dfrac{10^{-14}}{0.86\times 10^{-6}}$$

$$[H^{+}] = 1.162\times 10^{-3}$$

$$pH = - \log [H^{+}]= 7.94$$​​​​​

Answered by Abhisek | 1 year ago

### Related Questions

#### The concentration of sulphide ion in 0.1M HCl solution saturated with hydrogen sulphide is 1.0 × 10–19 M.

The concentration of sulphide ion in 0.1M HCl solution saturated with hydrogen sulphide is 1.0 × 10–19 M. If 10 mL of this is added to 5 mL of 0.04M solution of the following: FeSO4, MnCl2, ZnCl2 and CdCl2 . in which of these solutions precipitation will take place?

#### What is the minimum volume of water required to dissolve 1g of calcium sulphate at 298 K?

What is the minimum volume of water required to dissolve 1g of calcium sulphate at 298 K? (For calcium sulphate, Ksp is 9.1 × 10–6).

#### What is the maximum concentration of equimolar solutions of ferrous sulphate and sodium sulphide

What is the maximum concentration of equimolar solutions of ferrous sulphate and sodium sulphide so that when mixed in equal volumes, there is no precipitation of iron sulphide? (For iron sulphide, Ksp = 6.3 × 10–18).