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GeographyMediumAsked in: UPSC CAPF · CAPF 2021, Paper I

Which one of the following is not a type of chemical weathering?

  1. A.Carbonation solution
  2. B.Salt crystal growth
  3. C.Hydrolysis
  4. D.Oxidation

Correct answer

B. Salt crystal growth

Explanation

The correct answer is B, Salt crystal growth. Salt crystal growth breaks rock by pressure alone, without changing its minerals, so it is a type of physical (mechanical) weathering.

Weathering is the breaking down of rocks in place. Physical weathering splits rock into smaller pieces without altering its composition; it includes frost wedging, exfoliation caused by heating and cooling, unloading, and salt weathering. In salt weathering, salty water seeps into pores and cracks, evaporates and leaves crystals that grow and push the rock apart, which is common in deserts and on sea coasts. Chemical weathering changes the minerals themselves through reactions with water, air and acids, and is fastest in hot, wet climates.

A is wrong: carbonation and solution are chemical; carbonic acid in rainwater dissolves limestone and forms caves.

C is wrong: hydrolysis is chemical; water reacts with feldspar and turns it into clay.

D is wrong: oxidation is chemical; iron in rocks reacts with oxygen and rusts, giving a red colour.

Exam tip: chemical = solution, carbonation, hydration, hydrolysis, oxidation, reduction; physical = frost, exfoliation, salt crystal growth.

Practice Questions

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Q2.GeographyAsked in: CDS · CDS-II 2017, GKMedium

Which of the following statements is/are correct? 1. Himalayan rivers have their origin in the snow-covered areas, hence are dry in winter season. 2. Rivers of the Peninsular Plateau have reached maturity. 3. Himalayan rivers depict all the three stages of normal cycle of erosion. Select the correct answer using the code given below.

  1. A.2 only
  2. B.1 and 3 only
  3. C.2 and 3 only
  4. D.1, 2 and 3
Show answer
Correct answer: C. 2 and 3 only

Himalayan rivers are perennial, so statement 1 is wrong, while statements 2 and 3 are correct. Himalayan rivers such as the Ganga, Indus and Brahmaputra rise from glaciers and snowfields and also get monsoon rain, so they flow all year round, including in winter.

Q3.GeographyAsked in: CDS · CDS-II 2017, GKMedium

Which of the following statements related to latitude are true? 1. Rainfall, temperature and vegetation vary with latitude. 2. The difference between the longest day and the shortest day increases with latitude. 3. Indira Point is located approximately at 6°45' N latitude. Select the correct answer using the code given below.

  1. A.1 and 2 only
  2. B.1 and 3 only
  3. C.2 and 3 only
  4. D.1, 2 and 3
Show answer
Correct answer: D. 1, 2 and 3

All three statements about latitude are true. Latitude decides how directly the Sun's rays strike a place, so temperature, rainfall and the type of vegetation change from the equator towards the poles, from hot, wet rainforests to cold tundra.

Q4.GeographyAsked in: CDS · CDS-II 2017, GKMedium

Which of the following lakes is/are situated in Ladakh? 1. Tso Kar 2. Pangong Tso 3. Tsomgo 4. Tso Moriri Select the correct answer using the code given below.

  1. A.1 only
  2. B.2 and 3
  3. C.1, 2 and 4
  4. D.2 and 4 only
Show answer
Correct answer: C. 1, 2 and 4

Tso Kar, Pangong Tso and Tso Moriri are high-altitude lakes of Ladakh, while Tsomgo lies in Sikkim. Pangong Tso, at about 4,350 metres, is a long, narrow lake that stretches from Ladakh into Tibet, and most of its length lies on the Chinese side.