Science (086) — AI-generated practice question

When ethanol reacts with sodium metal, hydrogen gas is evolved and sodium ethoxide is formed:

$$2\text{Na} + 2\text{C}_2\text{H}_5\text{OH} \rightarrow 2\text{C}_2\text{H}_5\text{O}^-\text{Na}^+ + \text{H}_2\uparrow$$

This shows that only the O–H bond in ethanol is broken during this reaction, releasing hydrogen. The C–H bonds remain intact. This indicates that the O–H bond in ethanol is weaker and more reactive than the C–H bonds. The oxygen atom makes the O–H bond polar, allowing sodium to displace hydrogen easily, whereas C–H bonds are non-polar and relatively strong, making them unreactive with sodium.

Source: Chapter 4, Section 4.4.1 – Properties of Ethanol

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• Examiners expect the chemical equation for full marks — always include it.
• The key comparison is O–H (polar/reactive) vs C–H (non-polar/unreactive) — this is the core of the 3-mark answer.
• Mention that C–H bonds are not broken in this reaction; only the O–H bond reacts.
• The word "polar" is a bonus if you remember it, but saying "O–H is weaker/more reactive" is sufficient for CBSE.