GK
1-Permanent hardness of water, due to sulphates of the metal, can be destroyed by the use of Zeolites
2- Rust is a mixture of Fe2O3, 3H2O and FeO
3-The metallic constituents of hard water are Calcium, magnesium and iron
4-Old-written material, which cannot be read easily can be read by Infra Red rays
5-The type of glass used in making prisms and lenses is Flint glass
6-Hydrometer is an instrument used for measuring the specific gravity of liquids
7-Cholera is caused by vibrio cholerae
8-Cooking oil can be converted into vegetable ghee by the process of hydrogenation
9-The contact process is involved in the manufacture of Sulphuric acid
10-The location and energy of an electron in an atom can be specified by Quantum numbers
11-Bromine is a red liquid
12-Water has maximum density at 4°C
13-Iodine is obtained from sea weeds
14-The metal used in storage batteries is Lead
15-Hybridisation is cross-fertilisation between two varieties
16- The volume of water decreases when it is heated from 0°C to 5°C
17- Hydrogen bomb is based on the process of fusion
18-The life history of human malarial parasite in Anopheles was first described by Ronald Ross
19-Silver bromide is useful in photography
20-The buoyancy depends on the mass of the liquid displaced.