You must have seen tarnished copper vessels being cleaned with lemon or tamarind juice. Explain why these sour substances are effective in cleaning the vessels.
Name two metals which will displace hydrogen from dilute acids, and two metals which will not.
Give reasons : Carbonate and sulphide ores are usually converted into oxides during the process of extraction.
In the electrolytic refining of a metal $M$, what would you take as the anode, the cathode and the electrolyte ?
Give reasons : Platinum, gold and silver are used to make jewellery.