Science & Technology › Chemistry – UPSC Prelims PYQs

Water can dissolve more substances than any other liquid because

In India, the use of carbofuran, methyl parathion, phorate and triazophos is viewed with apprehension. These chemicals are used as

Which of the following is/are the example/examples of chemical change?

1. Crystallization of sodium chloride
2. Melting of ice
3. Souring of milk

Select the correct answer using the code given below.

Chlorination is a process used for water purification. The disinfecting action of chlorine is mainly due to

Which one of the following is used as an explosive ?

What is Bisphenol A (BPA)?

What is Agent Orange?

Who among the following discovered heavy water?

Which one of the following is also called Stranger Gas?

Which one of the following pairs of metals constitutes the lightest metal and the heaviest metal, respectively?

Which one of the following is another name of RDX?

Which one of the following non-metals is NOT a poor conductor of electricity?

Which one of the following is called Philosopher’s wool?

Which one of the following does not contain silver?

Consider the following chemicals:

1. Benzene
2. Carbon tetrachloride
3. Sodium carbonate
4. Trichloroethylene

Which of the above is/are used as dry-cleaning chemicals?

Consider the following statements :

1. Anhydrous sodium carbonate is commonly known as baking soda
2. Baking soda is used in fire extinguishers
3. Bleaching powder is manufactured in Hasenclever plant

Which of the statements given above is/are correct?

Consider the following statements:

1. Banking soda is used in fire extinguishers.
2. Quicklime is used in the manufacture of glass.
3. Gypsum is used in the manufacture of Plaster of Paris.

Which of the statements given above is/are correct?

Salts

of which of the following elements provide colours to fireworks?

Which one of the following statements is correct?

Consider the following statements The purpose of adding sodium sulphate and sodium silicate to the detergent in a washing powder is

1. To keep the washing powder dry
2. To maintain the alkalinity of the powder

Which of these statements is/are correct?

Assertion (A): In the periodic table of chemical elements, electron affinity is always found to increase from top to bottom in a group.

Reason (R): In a group, the atomic radius generally increases from top to bottom.

Assertion (A): Unsaturated fats are more reactive compared with the saturated fats.

Reason (R): Unsaturated fats have only single bonds in their structure.

With reference to ionic compounds, consider the following statements:

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

Which of these statements is/are correct?

Which one of the following statements is correct?

Which one of the following statements is correct?

Match List I (Oxidation number) with List II (The element) and select the correct answer using the codes given below the lists:

1. Oxidation number of Mn in MnO₂ B. 3 —
2. Oxidation number of S in H₂S₂O₇ C. 4 —
3. Oxidation number of Ca in CaO₂ D. 6 —
4. Oxidation number of Al in NaAlH₄

List I (Oxidation number) — List II (The element) A. 2 —

Assertion (A): With the increase of temperature, the viscosity of glycerine increases.

Reason (R): Rise of temperature increases kinetic energy of molecules.

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

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

Assertion (A): A chemical reaction becomes faster at higher temperatures.

Reason (R): At higher temperatures, molecular motion becomes more rapid.

Which of the following is correct?

Which one of the following is NOT radioactive?

Which one of the following is the correct sequence in increasing order of molecular weights of the hydrocarbons?

In an atom, the order of filling up of the orbitals is governed by

An aqueous solution of copper sulphate is acidic in nature because the salt undergoes

Consider the following statements with reference to the Periodic Table of chemical elements: I. Ionisation potential gradually decreases along a period. II. In a group of elements, electron affinity decreases as the atomic weight increases. III. In a given period, electronegativity decreases as the atomic number increases.

Which of these statement(s) is/are correct?

Match List I with List II

and select the correct answer using the codes given below the Lists:

List I I. German Silver II. Solder III. Bleaching Powder IV. Hypo

List II A) Tin B) Nickel C) Sodium D) Chlorine

Codes:

A small pouch containing silica gel is often found in bottles of medicine in tablet or powder form because silica gel

Match List I (Industrial processes) with List II (Industry with which associated) and select the correct answer using the codes given below the Lists:

List I I. Cracking II. Smelting III. Hydrogenation IV. Vulcanization

List II A) Rubber B) Petroleum C) Copper D) Edible fats

Codes:

Consider the following statements: Hard water is not suitable for I. Drinking. II. Washing clothes with soap. III. Use in boilers. IV. Irrigating crops.

Which of these statements are correct?

Assertion (A): To dilute sulphuric acid, acid is added to water and not water to acid.

Reason (R): Specific heat of water is quite large.

Match List I with List II

and select the correct answer using the codes given below the lists:

List I I. Potassium bromide II. Potassium nitrate III. Potassium sulphate IV. Mono-potassium tartrate

List II A. Fertiliser B. Photography C. Bakery D. Gunpowder

Codes:

Which one of the following metals does not form amalgams?

Consider the following statements about acetylene: I. It is used in welding industry. II. It is raw material for preparing plastics. III. It is easily obtained by mixing silicon carbide and water. Of these statements:

Match List I with List II

and select the correct answer using the codes given below the lists:

List I I. Blue vitriol II. Epsom salt III. Baking soda IV. Caustic soda

List II A) Sodium bicarbonate

B) Sodium hydroxide

C) Magnesium sulphate

Assertion (A): Formic acid is a stronger acid than acetic acid.

Reason (R): Formic acid is an organic acid.

Assertion (A): Phenyl is used as a household germicide.

Reason (R): Phenyl is a phenol derivative and phenol is an effective germicide.

Assertion (A): Sodium metal is stored under kerosene.

Reason (R): Metallic sodium melts when exposed to air.

Which one of the following was used as a chemical weapon in the First World War?

Which one of the following is present in the largest amount in terms of per cent by mass in the earth’s crust?

The characteristic odour of garlic is due to

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