RRB ALP GK Questions 2026

Litmus is a natural indicator obtained from lichens, which are a partnership between an alga and a fungus, and in a neutral solution it shows a purple colour.

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.

Cyclohexane is a closed ring of six carbon atoms joined by single bonds, and each carbon carries two hydrogen atoms, which gives C6H12.

The alkene series begins at two carbon atoms, so its first member is ethene, C2H4, and its second member is propene, C3H6.

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.

Put n equal to 3 in the alkyne general formula CnH2n-2 and the result is C3H4, which is propyne, the second member of the alkyne series.

An alkene is an unsaturated hydrocarbon in which two carbon atoms are joined by a double bond, so the carbon-to-carbon double bond is its identity.

Alkanes are saturated hydrocarbons, so every bond between two carbon atoms is a single bond and all the remaining valencies are filled by hydrogen.

The d-block sits in the middle of the periodic table, bridging the s-block on the left and the p-block on the right.

The halogens are placed in Group 17 of the modern periodic table. This family has five members - fluorine, chlorine, bromine, iodine and astatine.

An alkene carries one carbon-to-carbon double bond, and that bond uses up two hydrogen atoms that a saturated chain would have held, so the formula drops from CnH2n+2 to CnH2n. Putting n equal to 2 gives C2H4, ethene, the simplest alkene; n equal to 3 gives C3H6, propene.

Alkanes are saturated hydrocarbons in which carbon atoms are joined only by single bonds, and such a chain carries the largest possible number of hydrogen atoms, given by CnH2n+2.

Carbon is a non-metal, so it does not show metallic character; it neither loses electrons to form positive ions nor shows the lustre and malleability of metals.

An ionic compound is a lattice of positive and negative ions held by strong electrostatic attraction, and that force explains all its other properties.

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

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.

Ionic compounds dissolve well in water but not in kerosene, petrol or other non-polar organic solvents, so this statement is not a property of theirs.

The element with atomic number 56 is barium, and its outermost electron enters the 6s orbital, so it sits in the s-block.

Relative atomic mass is measured against the carbon-12 atom, one-twelfth of whose mass is taken as the standard unit. That unit is the atomic mass unit, written u, and it is defined as exactly one-twelfth of the mass of one atom of carbon-12.

Ice melts at 0 degrees Celsius, and 0 degrees Celsius is 273 K on the Kelvin scale. To change Celsius into Kelvin, add 273 to the Celsius reading, so 0 + 273 gives 273 K; the melting point of ice is usually written as 273.15 K in exact work.