UPSC 2023 Previous Year GK Questions with Answers

The correct answer is D, Oxygen. Of the four options, oxygen is by far the most plentiful element; it makes up about 46% of the Earth's crust by mass.

Oxygen is locked in rocks as silicates and oxides, makes up about 89% of the mass of water and about 21% of the air by volume. The order of elements in the crust is oxygen, silicon, aluminium, iron, calcium, sodium, potassium and magnesium. If the whole planet is counted, iron, concentrated in the core, rivals oxygen, but iron is not among the options here.

A is wrong: silicon is second in the crust, about 28%, mostly combined with oxygen in silica and silicates.

B is wrong: aluminium is third in the crust, about 8%, and the most abundant metal there.

C is wrong: carbon, though the basis of all life, is only a tiny fraction of the Earth's crust.

Exam tip: crust order O > Si > Al > Fe; most abundant metal in the crust = aluminium; most abundant gas in air = nitrogen.

The correct answer is A, Cu(I) and S of Cu2S. Copper in the +1 state is reduced to metal, so it is the oxidant; sulphur of Cu2S is oxidised, so it is the reductant.

Track the oxidation numbers. Copper goes from +1 in both Cu2O and Cu2S to 0 in metallic Cu: it gains electrons, is reduced, and therefore acts as the oxidising agent. Sulphur goes from −2 in Cu2S to +4 in SO2: it loses six electrons, is oxidised, and therefore acts as the reducing agent. Oxygen stays at −2 throughout. This self-reduction is the last step in extracting copper from copper glance in a Bessemer converter.

B is wrong: metallic Cu and the S of SO2 are products, not the species that cause the change.

C is wrong: oxygen keeps the same oxidation number, so it is neither oxidant nor reductant.

D is wrong: Cu(I) is the oxidant, but oxygen is not the reductant; sulphur is.

Exam tip: oxidant gets reduced (oxidation number falls); reductant gets oxidised (number rises).

The correct answer is C, Passing water through a cation exchange and an anion exchange resin bed. Together the two resins take out every dissolved ion, which leaves demineralised water.

In the cation exchange resin (written RH), metal ions such as Ca2+, Mg2+ and Na+ are swapped for H+ ions. The water then passes through the anion exchange resin (written R'OH), where chloride, sulphate and bicarbonate ions are swapped for OH− ions. The H+ and OH− so released join to form water, so no salt is left. This deionised water is used in laboratories, batteries and boilers.

A is wrong: a microfiltration membrane stops suspended particles and microbes, not dissolved salts.

B is wrong: Calgon (sodium hexametaphosphate) only ties up calcium and magnesium ions; the salts stay dissolved in the water.

D is wrong: boiling removes only temporary hardness caused by bicarbonates; chlorides and sulphates remain.

Exam tip: cation resin gives H+, anion resin gives OH−; both together = demineralised (deionised) water.

The correct answer is B, 1, 2 and 3 only. The first three are written into Article I of the SAARC Charter; ending cross-border terrorism is not one of its listed objectives.

The South Asian Association for Regional Cooperation was set up by the Charter signed at Dhaka on 8 December 1985, and its secretariat is in Kathmandu. Its objectives include promoting the welfare of the peoples of South Asia and improving their quality of life, strengthening collective self-reliance, contributing to mutual trust and understanding of one another's problems, and promoting collaboration in economic, social, cultural, technical and scientific fields. Terrorism is handled through a separate SAARC Regional Convention on Suppression of Terrorism (1987), not as a Charter objective.

A is wrong: it leaves out objective 3, which is in the Charter.

C is wrong: it adds statement 4, which is not a Charter objective.

D is wrong: it drops the true objectives 1 and 2 and adds statement 4.

Exam tip: SAARC, Dhaka Charter 1985, secretariat Kathmandu, eight members with Afghanistan joining in 2007.

The correct answer is B, Only two. Mahua and teak shed their leaves in the dry season, while the jackfruit tree is evergreen.

Deciduous trees drop all their leaves for a few weeks in the dry summer to save water; they make up India's tropical moist and dry deciduous forests, the most widespread forest type in the country. Teak is the best-known tree of these forests, found in Madhya Pradesh, Maharashtra, Karnataka and Kerala. Mahua is a deciduous tree of central India whose flowers are eaten and used to make liquor, and whose seeds give oil; it matters greatly to tribal communities. The jackfruit, by contrast, keeps its glossy leaves all year and grows in the humid Western Ghats and coastal regions.

A is wrong because two of the trees, not one, are deciduous.

C is wrong because the jackfruit is evergreen.

D is wrong because teak and mahua are typical deciduous trees.

Exam tip: teak, sal, mahua, sandalwood = deciduous; jackfruit, rosewood, mahogany = evergreen.

The correct answer is B, Only two pairs. Pairs 1 and 2 are correct; Visakhapatnam is not India's largest container port.

Kamarajar Port at Ennore, near Chennai in Tamil Nadu, was the first major port in India to be set up as a corporate entity, registered as a public company (Ennore Port Ltd). Mundra Port in Kutch, Gujarat, run by the Adani group, is the largest privately owned port in India. Visakhapatnam in Andhra Pradesh is a major port known for iron ore and bulk cargo and has a deep natural harbour, but the biggest container traffic is handled on the west coast, at Jawaharlal Nehru Port (Nhava Sheva) and Mundra.

A is wrong because two pairs, not one, are correct.

C is wrong because pair 3 is incorrect.

D is wrong because pairs 1 and 2 are correctly matched.

Exam tip: Kamarajar (Ennore) = first corporatised major port; Mundra = largest private port; container giants are on the west coast.

The correct answer is C, which is the statement that is not correct. The Kushana gold coins were struck on the same weight standard as the Roman aureus of the time, not on a different one, because the dynasty traded briskly with the Roman world and found it convenient to match that standard. The other three statements are sound. The Indo-Greeks issued the first Indian coins that carry the ruler’s name along with his portrait, a sharp change from the earlier punch-marked coins, which bore only symbols. The Kushanas, from Vima Kadphises and Kanishka onwards, issued the first gold coins in India in any quantity, with deities such as Shiva and the Buddha on the reverse. And their gold coins have indeed been found at many sites across north India and Central Asia, which is the clearest proof of how far their trade reached. Exam tip: punch-marked coins are the earliest, Indo-Greek coins the first with royal portraits, Kushana coins the first gold, and the Guptas issued the most gold coins.

The correct answer is D, 2 only. The United Nations works in six official languages, Arabic, Chinese, English, French, Russian and Spanish. Of the four names in the list, Arabic, Spanish and Chinese are all official, so only German, the second item, is not. Arabic was the last of the six to be added, in 1973. Of the six, English and French are also the working languages of the Secretariat.

Option A is wrong because Arabic is official, having been added in 1973. Option B is wrong for the same reason and because Chinese was official from the beginning as one of the languages of the founding members. Option C again wrongly counts Arabic as not official. Only option D keeps German alone, and German is not a UN language although Germany is a large contributor to the UN budget.

The correct answer is D, Statement-I is incorrect but Statement-II is correct. Rainforest soil is actually poor in nutrients, even though the forest above it is the richest on land. Heat and heavy rain make dead leaves decompose within weeks, and the released nutrients are taken up almost at once by the dense roots and fungi of the trees. So most nutrients are stored in the living biomass, not in the soil, and only a thin layer of humus lies on the surface. Constant rain also washes minerals down through leaching, leaving red, acidic, laterite-type soils rich mainly in iron and aluminium oxides. This is why cleared rainforest land loses its fertility after a few harvests. Statement-II is right because fast decomposition is exactly what this hot, wet climate causes. Options A and B are wrong because Statement-I is false. Option C is wrong because it reverses which statement is true. Exam tip: in a rainforest the nutrients sit in the trees, not the soil; cool forests keep more in the soil because decay is slow.

The correct answer is A, The International Union for Conservation of Nature. The Invasive Species Specialist Group (ISSG) is one of the expert groups of the IUCN's Species Survival Commission, and it manages the Global Invasive Species Database. The ISSG is a network of scientists and policy experts that gathers information on alien species that spread and harm native wildlife, and it also compiled the well-known list of '100 of the World's Worst Invasive Alien Species'. The IUCN, founded in 1948 and based at Gland in Switzerland, also publishes the Red List of Threatened Species. Invasive plants such as Lantana, water hyacinth and Prosopis juliflora are a major threat to Indian forests and wetlands. Option B is wrong because UNEP runs environmental programmes and conventions but not this specialist group. Option C is wrong because the World Commission on Environment and Development, the Brundtland Commission, is known for its 1987 report 'Our Common Future'. Option D is wrong because WWF is a separate conservation NGO. Exam tip: IUCN means the Red List, the Species Survival Commission and the invasive species database.

The correct answer is B, Only two. The government bond market and the stock market deal in long-term funds, so they are capital markets; call money and treasury bills belong to the money market. The dividing line is maturity: the capital market handles funds for more than one year, and the money market handles funds for up to one year. Government bonds, or dated securities, run for 5 to 40 years, and shares have no maturity at all. Call money is overnight lending between banks, with notice money for 2 to 14 days, and treasury bills are short-term government borrowing for 91, 182 or 364 days. The capital market is regulated by SEBI, while the money market is regulated mainly by the RBI. Option A is wrong because both bonds and shares are capital market segments. Option C is wrong because it would add one short-term market. Option D is wrong because call money and treasury bills are money market segments. Exam tip: over one year is capital market, up to one year is money market; T-bills are 91, 182 and 364 days.

The correct answer is A, Conducting 'Open Market Operations'. Sterilization means cancelling out the effect of foreign exchange operations on the domestic money supply, and the RBI does it mainly through open market operations. When dollars flow in and the RBI buys them to stop the rupee rising too fast, it releases rupees into the system, which can push up inflation. To neutralise this, it sells government securities and pulls the same amount of rupees back. When it sells dollars, it can buy securities to put rupees back in. Other tools used for this are the Market Stabilisation Scheme (from 2004), reverse repo and the Standing Deposit Facility. Option B is wrong because oversight of payment and settlement systems is about safe transactions, not the money supply. Option C is wrong because debt and cash management is the RBI's role as banker to the governments. Option D is wrong because regulating NBFCs is a supervisory function. Exam tip: buying dollars adds rupees, an OMO sale takes them back, and together that is sterilization.

The correct answer is D, Titanium. Ilmenite (FeTiO3) and rutile (TiO2) are the main ores of titanium, and India has large deposits of them in its beach sands. These heavy mineral sands occur mainly along the coasts of Kerala (Chavara), Tamil Nadu (Manavalakurichi) and Odisha (Chhatrapur), often together with monazite, zircon and garnet. Titanium is light, strong and does not rust, so it is used in aircraft, spacecraft and medical implants, while titanium dioxide is the white pigment in paints, paper and toothpaste. Option A is wrong because aluminium comes from bauxite, found mainly in Odisha and Jharkhand. Option B is wrong because copper comes from ores like chalcopyrite, mined at Khetri in Rajasthan and Malanjkhand in Madhya Pradesh. Option C is wrong because iron is taken from haematite and magnetite; ilmenite does contain iron, but it is mined for its titanium. Exam tip: ilmenite and rutile give titanium, monazite gives thorium and rare earths, and all three come from the black sands of the south-west and east coasts.

The correct answer is B, Jainism. Jainism holds that souls (jiva) live not only in humans, animals and plants but also in earth, water, fire and air. Jain thought ranks living beings by the number of senses they have. The lowest group, the one-sensed beings, includes earth-bodies, water-bodies, fire-bodies, air-bodies and plants, so even a stone or running water has a soul. This is why Jain monks practise ahimsa so strictly, sweeping the path and straining water so that they harm as few beings as possible. Mahavira taught that each jiva is bound by karma and is freed only through right faith, right knowledge and right conduct, the three jewels. Option A is wrong because Buddhism denies a permanent soul through its doctrine of anatta. Option C is wrong because Shaivism centres on devotion to Shiva and does not give souls to rocks. Option D is wrong because Vaishnavism centres on devotion to Vishnu and his avatars. Exam tip: souls in stones and water with the strictest ahimsa means Jainism; no soul (anatta) means Buddhism.

The correct answer is B, Only two. Bhaja is a Buddhist cave site and Sittanavasal a Jain one, but Besnagar has no Shaivite cave shrine. Besnagar, near Vidisha in Madhya Pradesh, is known for the Heliodorus pillar of about 113 BCE, a Garuda pillar set up by a Greek envoy who called himself a devotee of Vasudeva, so its link is Vaishnava. Bhaja, near Lonavala in Maharashtra, has some of the earliest Buddhist rock-cut chaityas and viharas, from about the second century BCE. Sittanavasal, near Pudukkottai in Tamil Nadu, is a Jain cave, the Arivar Koil, famous for its paintings of a lotus pond. So pair 1 is wrong and pairs 2 and 3 are right. Option A is wrong because two pairs match, not one. Option C is wrong because Besnagar is not a Shaivite cave site. Option D is wrong because Bhaja and Sittanavasal are correctly matched. Exam tip: Besnagar means Heliodorus and Vasudeva; Bhaja is Buddhist, Sittanavasal is Jain.

The correct answer is C, Bahadur Shah. The Sultan of Gujarat let the Portuguese take Diu in return for their help against the Mughal emperor Humayun. By the Treaty of Bassein (1534) Bahadur Shah handed Bassein to the Portuguese, and in 1535, with Humayun invading Gujarat, he allowed them to build a fort at Diu. Relations soon turned sour, and Bahadur Shah was killed in 1537 on a Portuguese ship off Diu. The Portuguese then held Diu, along with Daman and Goa, until India took them back in December 1961 through Operation Vijay. Option A is wrong because Ahmad Shah I founded Ahmedabad in the fifteenth century, long before the Portuguese arrived. Option B is wrong because Mahmud Begarha fought the Portuguese, joining the Egyptian fleet at Chaul (1508) and losing the Battle of Diu (1509). Option D is wrong because Muhammad Shah is not linked with the grant of Diu. Exam tip: Bahadur Shah, the Humayun threat, Diu fort to the Portuguese in 1535.

The correct answer is D, The Charter Act of 1833. This Act turned the Governor-General of Bengal into the Governor-General of India, with full civil and military powers over all British territory in India. Lord William Bentinck became the first Governor-General of India under it. The Act was the high point of centralisation: it took away the law-making powers of the Bombay and Madras governments, ended the East India Company's commercial activities so that it became a purely administrative body, and added a Law Member, Macaulay, to the Governor-General's Council. Option A is wrong because the Regulating Act of 1773 created the post of Governor-General of Bengal, first held by Warren Hastings. Option B is wrong because Pitt's India Act of 1784 set up the Board of Control and the system of dual control. Option C is wrong because the Charter Act of 1793 mainly renewed the Company's charter for twenty years. Exam tip: 1773 Governor-General of Bengal (Hastings), 1833 Governor-General of India (Bentinck), 1858 Viceroy (Canning).

The correct answer is A, 1st Amendment. It was passed in 1951 to undo court rulings that had used Fundamental Rights to strike down land reform and other laws. Courts had set aside zamindari abolition laws under the right to property, and in Romesh Thappar (1950) had read free speech very widely. The First Amendment Act, 1951 added the Ninth Schedule and Articles 31A and 31B to shield land reform laws, added 'public order', 'friendly relations with foreign States' and 'incitement to an offence' to Article 19(2), and added Article 15(4) for backward classes after the Champakam Dorairajan case. It was passed by the Provisional Parliament under Nehru. Option B is wrong because the 42nd Amendment of 1976 is known for 'socialist', 'secular' and the Fundamental Duties. Option C is wrong because the 44th Amendment of 1978 mainly undid Emergency excesses and removed property from Part III. Option D is wrong because the 86th Amendment of 2002 added Article 21A, the right to education. Exam tip: 1st Amendment, 1951, Ninth Schedule and Article 15(4).