Galvanisation is a method of protecting iron from rusting by coating with a thin layer of:

Metals are refined by using different methods. Which of the following metals are refined by electrolytic refining?

(i) Au (ii) Cu

(iii) Na (iv) K

Silver articles become black on prolonged exposure to air. This is due to the formation of:

Write true or false for the following statements:

Non-metals react with acids to give a salt and hydrogen gas.

Write true or false for the following statements:

At ordinary temperature, the surfaces of metals such as magnesium, aluminium, zinc, lead, etc., are covered with a thin layer of oxide which protects the metal from further oxidation.