Chemistry - 1 (Railways - RRB)

Hydrogen is used in the hydrogenation of vegetable oils to make vegetable ghee. 

Electron affinity is defined as the change in energy (in kJ/mole) of a neutral atom (in the gaseous phase) when an electron is added to the atom to form a negative ion. Halogens have the greatest electron affinity as by gaining one electron, they attain noble gas configuration. Thus, from the given elements, fluorine has the maximum electron affinity.

Coloured glass for goggles contains ferrous oxide.

Gold is soluble in aqua regia, which is a mixture formed by freshly mixing concentrated nitric acid and hydrochloric acid.

This is the correct option. Sodium carbonate is used as washing soda and for softening hard water.

Oxygen as a gas is highly compressible in nature. 

Isotopes of an element differ in their number of neutrons.

Au is the symbol of gold, which is a metal.

Solid CO₂ is also known as dry ice.

Sulphur molecule is polyatomic because its atomicity is 8. It exists in S₈ form.

The ion formed by the loss of one or more electrons by an atom is called a cation.

Food is cooked faster in a pressure cooker because high pressure increases the boiling point of water.

Iodine is an example of an element.

An electric bulb, on long use, forms a black coating on its inner surface due to sublimation of tungsten.

Vanilla essence is an example of olfactory indicator.

Naphthalene balls, which are used to repel moths and other insects, are obtained from coal tar.

The maximum number of electrons that can occupy a specific energy level can be found using the following formula:
Electron Capacity = 2n²
Thus, maximum number of electrons in N-shell will be = 2 x 4² = 32

The purest form of iron is wrought iron.

Bleaching powder used for disinfecting drinking water because it releases chlorine.

A tincture of iodine is a solid in liquid solution.