Question

A block of aluminium sinks in turpentine but floats in mercury.

Answer 1

1. For a body to float in liquid, its density must be less than that of the density of the liquid.
2. Since the density of aluminium (2.7 g cm^-3) < density of mercury (13.6 g cm^-3)
aluminium floats in mercury.

3. For a body to sink in liquid, its density must be greater than that of the density of the liquid.

4. Since the density of aluminium (2.7 g cm^-3) > density of turpentine (0.87 g cm^-3)
aluminium sinks in turpentine.
Hence, due to the larger density of aluminium as compared to the density of turpentine it sinks into it and it floats in mercury due to its less density compared to the density of mercury.