Define an alloy. How are alloys prepared ? How do the properties of iron change when :
(i) small quantity of carbon is mixed ?
(ii) nickel and chromium are mixed with it ?

Explanation

Alloy is a homogeneous mixture of two or more metals and non-metals. It is prepared by first melting the primary metal and then dissolving the other elements in it definite proportion. It is then cooled at room temperature.
(i) On mixing carbons, it becomes hard and strong.
(ii) On mixing Ni and Cr, it becomes hard and does not rust.