Answer these questions selecting the appropriate option given below:

Assertion: Iron is the most widely used metal. But it is never used in its pure state.

Reason: Pure iron is very soft and stretches easily when hot.

Both A and R are true and R is the correct explanation of A.

The correct answer is option 1. Both A and R are true and R is the correct explanation of A.

Iron is the most widely used metal. But it is never used in its pure state. This is because pure iron is very soft and stretches easily when hot. But, if it is mixed with a small amount of carbon (about 0.05 %), it becomes hard and strong. When iron is mixed with nickel and chromium, we get stainless steel, which is hard and does not rust. Thus, if iron is mixed with some other substance, its properties change.