Calculate pH of the following mixtures:
0.4 litre of 0.1 M NaOH and 0.2 litre of 0.05 M `C_2H_5COOH ``(k_a(C_2H_5COOH)=5.6` x `10^-6)`

Explanation

To calculate the pH of the mixture of 0.4 L of 0.1 M NaOH and 0.2 L of 0.05 M propanoic acid (C₂H₅COOH), we will follow these steps:

### Step 1: Calculate the moles of NaOH and C₂H₅COOH

1. **Calculate moles of NaOH:**
\[ \text{Moles of NaOH} = \text{Volume (L)} \times \text{Concentration (M)} = 0.4 \, \text{L} \times 0.1 \, \text{M} = 0.04 \, \text{moles} \]
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