Write notes on :

(i) Freon

(ii) CNG

(iii) Natural Rubber

(i) Freon: Freon is choloroflurocarbon refrigerant that contain carbon, chlorine and fluorine. They are mainly used in fridges & air conditioners and is one of the main reason for the depletion of ozone layer. Freon-10 is one example which is carbon tetrachloride. They are used as refrigerants in several electronic devices like refrigerators and air conditioners. They are also used as aerosol propellants. . When carbon tetrachloride reacts with hydrogen fluoride in the presence of SbCl₅ then Freon-11 is formed.

CCl₄ + HF → CCl₃F + HCl (in presence of SbCl₅)

(ii) CNG: CNG refers to Compressed Natural Gas which consists of methane. Carbon dioxide and water vapour are the only byproducts when CNG is burnt. It is light gas and when leaked gets mixed with the atmosphere. It is used as a fuel in vehicles and is a clean gas as it release low level of carbon dioxide.

(iii) Natural Rubber: Natural rubber is made up of a milky, runny material called latex obtained from stem of rubber tree. It consists of polymers of isoprene. Vulcanization is a chemical process for converting natural rubber into more durable material by heating them with sulphur which acts as an accelerator. Sulphur modify the polymer by forming cross-links between individual polymer chains. Vulcanized materials are less sticky and have superior mechanical properties.

Rubber is used for cements, for adhesive, insulating, and friction tapes; and for crepe rubber used in insulating blankets and footwear.