CDS GK Questions 2026

Soft soaps are potassium salts of fatty acids, while ordinary hard bar soaps are sodium salts. Soap is made by saponification, heating an oil or fat with an alkali.

Magnesium, calcium and barium are all alkaline earth metals of group 2, and each has a valency of 2. Elements in the same group of the periodic table have the same number of electrons in their outermost shell, and so the same valency.

The atmosphere is heated mainly from below, by the long-wave heat the Earth's surface gives off, not directly by sunlight.

Their valencies are neon 0, magnesium 2, nitrogen 3 and silicon 4. Valency is the combining capacity of an atom, the number of electrons it loses, gains or shares to reach a stable octet.

Electric power is P = V × I, and 220 V × 0.6 A = 132 W. Power is the rate at which electrical energy is used, measured in watts; one watt is one joule per second, or one volt times one ampere.

Mitochondria are membrane-bound organelles, and only eukaryotic cells have membrane-bound organelles. Prokaryotes such as bacteria and cyanobacteria have no true nucleus and no membrane-bound organelles; their DNA lies in a region called the nucleoid, and they carry out respiration on their plasma membrane.

Statements 1, 3 and 4 describe Shankardeva correctly; statement 2 is wrong because Gaudiya Vaishnavism was founded by Chaitanya Mahaprabhu of Bengal.

Inside a long current-carrying solenoid the magnetic field has the same strength and direction at every point, shown by parallel, evenly spaced field lines.

A work done that is fixed by the starting and ending speeds alone is exactly what the work-energy theorem states: W(net) = ½mv² − ½mu².

Of the three forms of carbon, only fullerenes are made of closed, hollow, cage-like molecules. The best-known fullerene is buckminsterfullerene, C60, a hollow sphere of 60 carbon atoms arranged in 20 hexagons and 12 pentagons, shaped like a football.

The Taklamakan lies in the Tarim Basin of Xinjiang in north-western China, in the heart of Central Asia. The Taklamakan is a cold, sandy desert ringed by high mountains: the Kunlun to the south, the Tian Shan to the north and the Pamirs to the west.

A simple periscope has two plane mirrors, and light reaches the eye only by bouncing off them. In a simple periscope, two plane mirrors are fixed parallel to each other at the two bends of a long tube, each tilted at 45° to its length.

A mixture of carbon monoxide and hydrogen is called synthesis gas, or syngas, because it is the starting material for making methanol and many other compounds.

This is sodium stearate, the sodium salt of a long-chain fatty acid, which makes it a soap and not a synthetic detergent.

This statement is false: water is a strongly polar molecule. In a water molecule the oxygen atom is much more electronegative than hydrogen, so it pulls the shared electrons towards itself and carries a partial negative charge, while the two hydrogens carry partial positive charges.

This is the incorrect statement: the world has 36 recognised biodiversity hotspots, far fewer than 100. The hotspot idea came from the British ecologist Norman Myers, who in 1988 named ten tropical forest regions that were very rich in species and under heavy threat.

Argon has atomic number 18, and a neutral atom has as many electrons as protons, so it has 18 electrons.

X-rays have wavelengths of roughly 0.01 nm to 10 nm, so 1 nm sits right inside the X-ray band. The electromagnetic spectrum runs, from the shortest wavelength to the longest, as gamma rays, X-rays, ultraviolet, visible light, infrared, microwaves and radio waves.

Meiosis makes gametes that differ from one another, and fertilization joins a gamete from each of two parents, so every offspring gets a new mix of genes.

Statements 2 and 3 are correct; statement 1 is wrong because the earliest inscriptions are in Prakrit, not Sanskrit.