Calcination is the process of heating the concentrated ore to a high temperature in the absence or limited supply of air. In this process metal carbonates are oxidised to metal oxide. It is very useful in metallurgy process to extract metal. For example, FeCO 3 s → Calcination FeO s + CO 2 g

Which of the following reactions is possible? (i) ZnSO 4 aq + Cu s → CuSO 4 aq + Zn s (ii) Zn s + CuSO 4 aq → ZnSO 4 aq + Cu s

From the given reactions, only the (ii) reaction is possible. That is, Zn s + CuSO 4 aq → ZnSO 4 aq + Cu s Here, zinc is more reactive than copper. Therefore, it can replace copper from copper sulphate solution. That is, in general, a more reactive metal can replace the less reactive metal from its solution. Hence, the given reaction is a single displacement reaction.

An alloy is a homogeneous mixture of two or more metals or a metal and non-metal. Alloys are non-corrosive and durable. For example, i. Stainless steel is an alloy of iron with nickel and cobalt. It is used for vessels, construction etc. ii. Brass is an alloy of copper and zinc. It is used in machinery parts.