Identify the following terms / compounds: (a) A compound which reacts with water to give acetylene gas. (b) The gas evolved when sodium propanoate is heated with soda lime. (c) A reddish-brown precipitate formed when ferric chloride solution reacts with an alkali. (d) A pair of electrons present in an atom which is not shared with any other atom during bond formation. (e) The relative molecular mass of a substance expressed in grams.

Match Column A with Column B: Column A Column B (a) CuO + C ⟶ Cu + CO 1. Oxidation (b) Al3+ + 3e− ⟶ Al 2. Ionisation (c) PbBr2 ⟶ Pb2+ + 2Br1− 3. Reduction (d) 2O2− − 2e− ⟶ O2 4. Redox (e) HCl ⟶ H+ + Cl1− 5. Electrolytic dissociation

K, L and M are beakers containing three different solutions as shown below. Name the beaker which: (a) contains only ions. (b) contains only molecules. (c) has pH less than 7.

Zn + 4HNO3 ⟶ Zn(NO3)2 + 2H2O + 2NO2 32.5 g of zinc reacts with concentrated nitric acid as given in the above equation. (a) How many moles of zinc was required in the reaction? (b) Find the mass of nitric acid needed to react with 32.5 g of zinc. (c) Find the volume of nitrogen dioxide liberated in (b). [Atomic weight: H=1, N=14, O=16, Zn=65]

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?

5.6 litres of gas Z weighs 32 g at STP. What is the molecular weight and vapour density of Z?

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.

The diagram given below shows the electroplating of a spoon with silver. With reference to the diagram, answer the following questions: (a) Write an equation for the reaction that occurs at the cathode. (b) Silver nitrate solution is not preferred as an electrolyte in the above process. Give a reason. (c) Why is alternating current not used in the process? (d) What is the observation at the anode?

Equal volumes of ammonia gas and chlorine gas are kept in two different containers under the same conditions of temperature and pressure. Find the number of molecules contained in chlorine gas when the mass of ammonia is 34 g. [Atomic weight: Cl=35.5, H=1, N=14]

Differentiate between the following pairs based on the criteria given in the bracket: (a) Acetic acid and Sulphuric acid (number of replaceable hydrogen ion per molecule) (b) Electrolyte and Metallic conductor (the particles conducting electricity)

Element A belongs to group 15 and period 2 of the Periodic Table. (a) Identify the element A. (b) Write the formula of the compound formed when element A combines with hydrogen. (c) Draw the dot (•) and cross (×) structure of the compound formed in (b) above.

Alex was given a solution of an unknown salt Y for analysis. He performed the following tests and recorded his observations: To a part of the solution Y, he added silver nitrate solution and obtained a white precipitate which was soluble in ammonium hydroxide solution. To the remaining solution he added a few drops of sodium hydroxide solution and obtained a pale blue precipitate. Based on the observations made by Alex, identify: (a) the anion and (b) the cation present in salt Y.