Write ‘true’ or ‘false’ for the following statements :
(a) No new substance is formed during a chemical reaction
(b) Hydrogen sulphide has rotten egg smell :
(c) When potassium iodide solution is added to lead acetate solution a red precipitate is formed
(d) A black residue is formed when sugar is heated
(e) When iron and sulphur are heated together a grey mass is formed which is attracted by a magnet
(f) A chemical equation gives only qualitative information of a chemical reaction