P, Q, R and S are four metals. Both P and Q react with concentrated alkali and also with steam. Reaction of P with steam is rapid in the beginning and becomes slow later.Oxide of R on treatment with P liberates huge amount of heat and R produces brown coloured flakes on exposure to humid atmosphere. S forms two types of oxides below 1370 K and above 1370 K. Identify P, Q, R and S and write all the balanced chemical equations.
Since, P and Q react with concentrated alkali, they are $Al$ and $Zn$. Reaction of P with steam is rapid in the beginning and becomes slow later. Hence, P is $Al$Since, oxide of R produces huge amount of heat with P and produces brown coloured flakes in humid atmosphere, it is iron ($Fe$).As S forms two types of oxides above and below 1370 K, it is copper ($Cu$).