Give reason : Paper by itself catches fire easily whereas a piece of paper wrapped around an aluuminium pipe does not,

Give reasons : i) lonic compounds in solid state do not conduet electricity, whereas in molten state are good conductors of electricity. (ii) ii) Silver articles when exposed to air gradually turn blackish. ii) Chenmical reaction does not take place when copper is added to iron sulphate solution.

Give reason : (i) Ionic compounds in solid state do not conduct electricity, whereas in molten state are good conductors of electricity. (ii) Silver articles when exposed to air gradually turn blackish. (iii) Chemical reaction does not take place when copper is added to iron sulphate solution.

(i) You have three unlabelled test-tubes containing ethanol, ethanoic acid and soap solution. Explain the method you would use to identify the compounds in different test tubes by chemical tests using litmus paper and sodium metal. (ii) Give the reason of formation of scum when soaps are used with hard water.

Dry HCl gas does not change the colour of dry blue litmus paper . Give reasons.

When a metal X is treated with cold watr, it gives a base Y with molecular formula XOH (molecular mass 40) and liberates a gas Z which easily catches fire. Identify X, Y and Z