RRB Group D 2025 Previous Year GK Questions with Answers

Concentration tells how much solute is present in a given amount of solution, and the three standard percentage forms are mass by mass, mass by volume and volume by volume; volume by mass is not one of them.

The Tyndall effect is the scattering of a beam of light by particles suspended in a medium, and it needs particles large enough to scatter that light.

A haloalkane carries a halogen atom - fluorine, chlorine, bromine or iodine - bonded to a carbon chain, so no oxygen appears in its functional group at all.

C3H4 is propyne, and it fits the alkyne general formula CnH2n-2 when n equals 3. Alkynes are unsaturated hydrocarbons that carry at least one carbon-to-carbon triple bond, and the first member of the family is ethyne, C2H2, better known as acetylene and burnt with oxygen in welding torches.

A covalent bond is formed when two atoms share one or more pairs of electrons so that each completes its outermost shell.

A metal loses electrons and a non-metal gains them, so the transfer makes oppositely charged ions that attract each other, and that attraction is an ionic bond.

Sodium is a metal that gives up an electron easily and chlorine is a non-metal that accepts one, so the two form sodium chloride, an ionic compound.

The book tells the story of the Christian Medical College at Vellore, one of India's oldest teaching hospitals, and it was written by Dr. V I Mathan, a physician long associated with that institution.

An iron rod is a solid, and the force of attraction between particles is strongest in the solid state. In a solid the particles sit close together in fixed positions and can only vibrate, so a solid keeps its shape, has a definite volume and can hardly be compressed.

Force has to be applied to break the chalk because its particles hold one another together, and that pull is the force of attraction between particles.

Test Cricket: A History, published in 2025, was written by the English cricket writer and journalist Tim Wigmore.