Give one significant observation when: (a) Barium chloride solution is added to zinc sulphate solution. (b) Lead nitrate is heated strongly. (c) Chlorine gas is passed through moist starch iodide paper.

Give balanced equations for the following: (a) Action of dilute hydrochloric acid on ammonium carbonate. (b) Oxidation of sulphur with hot concentrated nitric acid. (c) Reaction of concentrated sulphuric acid with carbon.

Name the gas produced during each of the following reactions: (a) When copper is treated with hot, concentrated nitric acid. (b) When ammonia is burnt in an atmosphere of oxygen. (c) When ferrous sulphide reacts with dilute hydrochloric acid.

Carbon reacts with an acid to form carbon dioxide, water and nitrogen dioxide. (a) Name the acid used in the reaction. (b) Write a balanced chemical equation for the reaction that occurs.

Study the reaction given below and answer the questions that follow: (a) Give one reason for maintaining the temperature below 200°C. (b) Why is concentrated Sulphuric acid used in the above reaction?

Complete and balance the following equations: (a) NH4Cl + Ca(OH)2 → (b) CuSO4 + NH4OH → (c) Cu + Conc. HNO3 →

Anil is a laboratory assistant in a college. He prepared nitric acid but stored it in a transparent container exposed to sunlight. After a few days, brown fumes were observed in the container and the acid turned slightly yellowish in colour. (a) What was the error made by Anil while storing the acid? (b) Why were brown fumes observed in the container? (c) How can the yellowish tinge in the acid be removed?

Complete the following sentences by choosing the correct option from the brackets: (a) The oxide that dissolves in caustic potash (KOH) is ............... . [ZnO / CuO] (b) The reaction that takes place at the anode during the electrolysis of molten lead bromide is ............... . [2Br − 2e− ⟶ 2Br− / 2Br− − 2e− ⟶ Br2] (c) The volume occupied by 8 grams of oxygen gas at STP is ............... litres. [5.6 / 8.96] [Atomic weight of O = 16] (d) ............... does not give hydrogen gas when it reacts with cold and very dilute nitric acid. [Cu / Mn] (e) ............... is a polar covalent compound. [HCl / CCl4]

Give balanced equations for the following: (a) Copper reacts with concentrated Nitric acid. (b) Aluminium nitride is treated with warm water.

The nitrate which on thermal decomposition leaves behind a residue which is yellow when hot and white when cold: (a) Lead nitrate (b) Ammonium nitrate (c) Copper nitrate (d) Zinc nitrate

The salt formed when concentrated sulphuric acid reacts with KNO3 above 200°C: (a) K2SO4 (b) K2SO3 (c) KHSO4 (d) KHSO3

(a) State Avogadro’s Law. (b) Define Co-ordinate bond.