NDA GK Questions 2026

Vegetable oils are hardened into margarine and vanaspati ghee by hydrogenation. Liquid vegetable oils are unsaturated: their fatty-acid chains contain carbon-carbon double bonds.

This matches the reactivity series, which lists metals from the most to the least reactive. Sodium is near the top: it reacts violently with cold water and is stored under kerosene.

Temporary hardness is caused by the bicarbonates (hydrogencarbonates) of calcium and magnesium dissolved in water. It is called temporary because it can be removed simply by boiling: on heating, the soluble bicarbonates break down into insoluble carbonates, or magnesium hydroxide, which settle out, and carbon dioxide escapes.

Quick lime is calcium oxide (CaO), which contains no carbonate, so it gives no carbon dioxide with an acid. Acids release carbon dioxide only from carbonates and hydrogencarbonates: the general reaction is metal carbonate plus acid gives salt, water and carbon dioxide.

Plaster of Paris is made from gypsum, not from common salt. When gypsum, calcium sulphate dihydrate (CaSO4·2H2O), is heated to about 373 K, it loses part of its water and becomes calcium sulphate hemihydrate (CaSO4·½H2O), which is Plaster of Paris; it sets hard again when mixed with water and is…

Anthracene sublimes on heating, while common salt does not, so heating the mixture separates them. Sublimation is the change of a solid directly into vapour without passing through the liquid state.

A honeybee sting injects methanoic acid, also called formic acid (HCOOH), which causes the burning pain and irritation.

Potassium hydroxide gives potassium soaps, which are softer and milder than sodium soaps. Saponification is the reaction in which an oil or fat is heated with an alkali to give soap, the sodium or potassium salt of a long-chain fatty acid, and glycerol.

Rain water is the purest natural form of water because it is formed by evaporation and condensation, a natural distillation.

The Ahmedabad mill strike of 1918 was Gandhi's satyagraha for industrial workers. A dispute arose between the cotton mill owners and the workers over the plague bonus, which the owners wanted to withdraw.

Balakot, along with Nageshwar in Gujarat, is described as a specialised centre for making shell objects. Both settlements lay near the coast, where shells were easy to collect, and excavations there have found large amounts of shell waste, unfinished pieces and finished items.

Surge pricing is a form of dynamic pricing in which the price moves up when demand rises faster than the available supply.

The Constitution gives the Supreme Court no such jurisdiction; the collegium is only the system by which senior judges recommend appointments.

Among the four, Charan Singh held office for the shortest time, about 170 days. He became Prime Minister on 28 July 1979 after the Janata government of Morarji Desai fell, but resigned on 20 August 1979 without ever facing Parliament, when the Congress withdrew its support.

Dryland farming is practised where annual rainfall is below about 75 cm. Indian agriculture is grouped by the source of moisture into irrigated and rainfed farming, and rainfed farming is further divided into dryland and wetland farming.

Relative humidity compares the moisture in the air with what the air could hold, and that capacity rises with temperature.

Thawing is the melting of ice, a physical change that works on rocks only mechanically.

Tuff is the rock formed when volcanic ash settles in layers and hardens.

Temperature inversion needs rapid cooling of the ground, which happens under clear skies, not cloudy ones. Statement I is correct: normally temperature falls with height, but during an inversion a layer of warmer air lies above cooler air near the ground, so the normal lapse rate is reversed.

Both the Steppes and the Pampas are mid-latitude grasslands, so only the first statement is right.