In which sentence is the word ‘iron’ used as a countable noun?

The correct answer is Option (1) → Mummy switched off the iron after pressing my school shirt.

Countable and uncountable uses of a noun:

• Some nouns cannot be counted when they name a substance. But they can be counted when they name a thing.
• In Option 1, “the iron” is the thing we use to press clothes. We can count it: one iron, two irons. So it is countable.

Why the Other Options are Incorrect?

Option 2: Spinach is a good source of iron. — Incorrect. Here “iron” is a substance found in food. It cannot be counted.

Option 3: The old gate of our colony is made of iron. — Incorrect. Here “iron” is the metal the gate is made of. A metal cannot be counted.

Option 4: Iron rusts quickly in the damp monsoon air. — Incorrect. Here “iron” means the metal in general. It cannot be counted.