The ionisation constant of methylamine ` (CH_3 NH_2) " is " 4.4 xx 10 ^(-5) ` . Calculate the pH of its 0.2 M solutions.

Explanation

To calculate the pH of a 0.2 M solution of methylamine (CH₃NH₂) with an ionization constant (Kₐ) of 4.4 × 10⁻⁵, we can follow these steps:

### Step 1: Write the ionization reaction
Methylamine reacts with water as follows:
\[ \text{CH}_3\text{NH}_2 + \text{H}_2\text{O} \rightleftharpoons \text{CH}_3\text{NH}_3^+ + \text{OH}^- \]

### Step 2: Set up the equilibrium expression
The equilibrium expression for the base ionization constant (Kₐ) is given by:
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