An element A belongs to 14th group is a metal, which can be cut with a knife. It is not a good conductor of heat and electricity. A in pure state does not react with water but air dissolved water forms hydroxide. Identify A.

An element A belongs to 14th group and occupies period number 6. A reacts with conc. HCl to give B an acid. A is used to prepare C which is used as an antiknock in automobilies. Identify the element A and the compounds B and C write the reactions

Give an example of a metal which (i) is a liquid at room temperature. (ii) can be easily cut with a knife. (iii) is the best conductor of heat. (iv) is a poor conductor of heat.

In the light of metallic bonding account for the following properties of group 2 elements. a. These are harder than alkali metals b. These are good conductors of heat and electricity.

(i) A non-metal X exists in two different forms Y and Z. Y is the hardest natural substance whereas Z is a good conductor of electricity. Identify X, Y, Z. (ii) A element, X, on reaction with oxygen forms an oxide XO_(2) . The Oxide when dissolved in water turns blue litmus red. State whether element X is a metal or a non-metal. (ii) Name the metal which is alloyed with copper to make bronze.

An element A occupies group number 17 and period number 2, shows anomalous behaviour . A reacts with water forms a mixture of B,C and acid D. B and C are allotropes. A also reacts with hydrogen violently even in dark to given an acid D. Identify A,B,C and D write the reactions.

Translate the following statements into chemical equations and then balance them . (a)Hydrogen gas combines with nitrogen to form ammonia . (b) Hydrogen sulphide gas burns in air to give water and sulphur dioxide. (c) Barium chloride reacts with aliminium sulphate to give aluminium chloride and a precipitate of barium sulphate. (d) Potassium metal reacts with water to give potassium hydroxide and hydrogen gas .