Rancidity can be defined as the chemical decomposition of oils and fats when exposed to air, light, moisture, and bacterial activity in food and other products making them undesirable for consumption. It can be prevented by the following methods: The packing of food materials should replace the air with Nitrogen. The food materials should be placed at very low temperatures. The addition of antioxidants also prevents rancidity process.

Name the factors that affect the rate of a reaction. Explain in detail.

The factors that affect the rate of reaction are as follows- Nature of reactants Concentration of the reactants Temperature Catalyst Pressure Surface area of the reactants Nature of reactants- Nature or reactivity influences the rate of reaction. For example Aluminium is more reactive than Zinc, and therefore, the rate of reaction of aluminium with hydrochloric acid is more than that with the zinc. Concentration of the reactants- The rate of reaction increases with the increase in the number of concentration of the reactants Temperature- Higher the temperature, faster will be the reaction and thus, rate of reaction will also increase. For example- Food kept at room temperature spoils faster than kept inside the refrigerators. Pressure- If reactants are gasses, then increasing the pressure increases the rate of reaction. This is because particles come closer and collide frequently. Catalyst- It is a substance that increases the rate of a reaction without being consumed in the reaction. Surface area- The rate of reaction increases with an increase in the surface area of the reactants. For example-Powdered calcium carbonate reacts more readily with hydrochloric acid than marble chips.

What is polymerisation? Write name and main uses of any three polymers.

Polymerisation is defined as the chemical process in which the monomers are joined together to form polymers. Thus, a polymer is a large single chain-like molecule in which the repeating units derived from small molecules called monomers are bound together. The name and main uses of the three polymers are as follows- Polymer Monomer Uses Rubber Isoprene (1, 2-methyl 1 – 1, 3-butadiene) Making tyres, elastic materials BUNA-S (a) 1, 3-butadiene (b) Styrene It is used for manufacturing automobile tyres. It is used for making floor tiles, footwear components, cable insulation etc. BUNA-N (a) 1, 3-butadiene (b) Vinyl Cyanide It is used in the automotive and aeronautical industries to make fuel and oil handling hoses, seals, and protective gloves in the nuclear industry.