Quiz 220 – UPSC Previous Year’s Chemistry Questions

The characteristic odour of garlic is due to-

(a) a chloro compound

(b) a sulphur compound

(c) a fluorine compound

(d) acetic acid


The characteristic odour of garlic is due to sulphur compound. Due to the sulphur compound garlic have many medicinal properties.

Ans- (b)


The most reactive among the halogens is-

(a) fluorine

(b) chlorine

(c) bromine

(d) iodine


It is the halogen group that contains the given components. The reactivity decreases from top to bottom in this group. The reactivity decreases in the following order-

Fluorine > chlorine > bromine > iodine

Ans- (a)


Which of the following is an active component of oil of clove?

(a) Menthol

(b) Eugenol

(c) Menthanol

(d) Benzaldehyde


Eugenol is an active component of oil of clove. It has many medicinal properties.

Ans- (b)


Which of the following is not an essential micronutrient for plants?

(a) Boron

(b) Zinc

(c) Sodium

(d) Copper


Boron, Zinc and Copper are essential micronutrients required by plant for it’s healthy growth, sodium is not an essential micronutrient.

Ans- (c)


Which one of the following materials is very hard and very ductile?

(a) Carborundum

(b) Tungsten

(c) Cast iron

(d) Nichrome


Nichrome has high melting point because it is very ductile. The metal is very hard and non-fragile.

Ans- (d)


Which one of the following is NOT radioactive?

(a) Astatine

(b) Francium

(c) Tritium

(d) Zirconium


Zirconium is not a radioactive substance.

Ans- (d)


With reference to ionic compounds, consider the following statements:

  1. Ionic compounds are insoluble in alcohol.
  2. Ionic compound in the solid state are good conductor of electricity.

Which of these statements is/are correct?

(a) only 1

(b) only 2

(c) Both 1 and 2

(d) Neither 1 nor 2


Ionic compounds are readily soluble in water but insoluble in organic solvent like ether, alcohol, acetone. Ionic compounds in solution are good conductor because there are no free ions to carry charge.

Ans- (a)


Regarding the atom of a chemical element, the magnetic quantum number refers to-

(a) orientation

(b) shape

(c) size

(d) spin


Regarding the atom of a chemical element, the magnetic quantum numbers refers to orientation.

Ans- (a)


Salt of which of the following elements provide colours to fireworks?

(a) Zinc and Sulphur

(b) Potassium and Mercury

(c) Strontium and Barium

(d) Chromium and Nickel


Strontium and barium, both belongs to group 2 of the periodic table. They are also called alkaline earth metals. They have common property of getting tarnished in air due to their high reactivity and imparting characteristic colour to firworks.

Strontium nitrate produced red colour while barium nitrate produces green flames in pyrotechry, barium chlorate is used in producing green flames.

Ans- (c)


Assertion (A): Synthetic detergents can lather well in hard water.

Reason (R): Synthetic detergents form soluble calcium and magnesium salt with hard water.

(a) Both A and R are true and R is the correct explanation of A.

(b) Both A and R are true but R is not the correct explanation of A.

(c) A is true but R is false

(d) A is false but R is true.


Hard water contains chloride and sulphate salt of magnesium and calcium. Synthetic detergents form soluble calcium and magnesium salt with hard water.

Ans- (a)

Related Articles:

Quiz 217 – Previous Year’s Science Questions

Quiz 214 – UPSC Previous Year’s History Questions

Quiz 209 – Geography Previous Year’s Questions

Quiz 205 – Science Previous Year’s Questions

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  1. One of the questions regarding ionic compounds, both the statements are true, hence correct option would be (c)

    • electrons cannot move freely in solid state. Hence ionic compounds are bad conductors of electricity.
      option would be (a)

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