The heats of solution of one mole of Na and that of `Na_2O ` in water under standard conditions are -183.79 kJ/mol and -237.94 kJ/mol respectively, water being taken in large excess in both the cases. Calculate the standard heat of formation of sodium oxide if the standard heat of formation of water is –285.84 kJ/mol.

Explanation

To calculate the standard heat of formation of sodium oxide (Na2O) using the given heats of solution and the heat of formation of water, we can follow these steps:

### Step 1: Write the relevant reactions and their enthalpy changes.

1. **Dissolution of Sodium (Na) in Water:**
\[ 2 \text{Na (s)} + 2 \text{H}_2\text{O (l)} \rightarrow 2 \text{NaOH (aq)} + \text{H}_2 (g) \quad \Delta H = -183.79 \text{ kJ/mol} \]
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