When roasting is carried out:

(P) Sulphide ores are converted into oxide and sulphate 

(Q) Remove water of hydration

(R) Melt the ore 

(S) Remove arsenic and sulphur impurities of these statements:

Sulphide ores are transformed into oxide and sulphate during roasting. It removes hydration water. It eliminates arsenic and sulphur contaminants.

By heating ore below its melting point in the presence of extra air, roasting is a metallurgical process that turns ore into its oxide. Roasting is a technique used to convert sulphide ores, whereas calcination is often used to oxidise carbonates.