Question

The volume of a substance ‘X’ cannot be increased or decreased by reducing or increasing pressure upon it. ‘X’ can be

• A. iron block
• B. sponge
• C. piece of bread
• D. air

Answer 1

The correct option is A iron block

Air is a gas and gases are compressible, i.e., they can undergo a change in volume when the pressure in altered.
Iron block is a solid and solids generally have a fixed volume, which cannot be altered by a change in pressure. Sponge and bread are exceptions because they have minute pores in them. So, ‘X’ can be iron block.
Hence, the correct answer is option (a).