Explanation

Aluminium has a valency of 3 because it loses three electrons to achieve a stable electron configuration.

Its atomic number is 13.

Its electron configuration is 2, 8, 3.

This means it donates three electrons to form Al³⁺ ions.

Explanation

After the failure of the 1857 War of Independence, the British government ended the rule of the East India Company.

India then came directly under the British Crown’s control, starting the period known as the British Raj.

Explanation

Lord Birkenhead, the British Secretary of State for India, insulted Indian leaders, claiming they couldn't agree on a constitution.

His remarks prompted Indian leaders to form the Nehru Report (1928) as a counter-proposal.

Explanation

Maulana Muhammad-ul-Hassan (also known as Hasrat Mohani) was famously called the Prisoner of Malta due to his imprisonment by the British.

He was jailed for his anti-British activities and later exiled to Malta, hence the title.

Explanation

The Jinnah-Gandhi talks occurred from September 9 to September 27, 1944.

During this period, 24 letters were exchanged between Muhammad Ali Jinnah and Mahatma Gandhi.

Explanation

A wind vane, also called a weather vane.

It is an instrument used to determine the direction of the wind.

It typically has an arrow that points into the direction from which the wind is blowing.

Explanation

Mesosomes are infoldings of the bacterial plasma membrane that help in cellular respiration, DNA replication, and cell division.

Since bacteria lack mitochondria, mesosomes function similarly to mitochondria by aiding in ATP (energy) production.

Explanation

The maximum number of electrons in any shell is determined by the formula 2n², where n is the principal quantum number.

This formula comes from quantum mechanics and defines the electron capacity of energy levels in an atom.

Explanation

Paper chromatography is a simple and widely used method for separating and analyzing mixtures of substances.

It relies on capillary action, where components of a mixture travel at different speeds on a paper strip due to differences in solubility.

Explanation

The gear system helps control speed and force by changing the torque applied to the wheels.

The wheel and axle mechanism allows smooth movement and efficient transfer of energy.