Chemistry PYQs

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1. Prelims 2004Q124Chemistry

   Match List I (Fuel Gases) with List II (Major Constituents) and select the correct answer using the codes given below:

   List I

   A.CNG

   B.Coal gas

   C.LPG

   D.Water gas

   List II

   1.Carbon monoxide, Hydrogen

   2.Butane, Propane

   3.Methane, Ethane

   4.Hydrogen, Methane, Carbon monoxide

   aA-2, B-1, C-3, D-4bA-3, B-4, C-2, D-1cA-2, B-4, C-3, D-1dA-3, B-1, C-2, D-4
2. Prelims 2004Q127Chemistry

   Standard 18-carat gold sold in the market contains

   a82 parts gold and 18 parts other metalsb18 parts gold and 82 parts other metalsc18 parts gold and 6 parts other metalsd9 parts gold and 15 parts other metals
3. Prelims 2004Q129Chemistry

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

   aZinc and sulphurbPotassium and mercurycStrontium and bariumdChromium and nickel
4. Prelims 2003Q29ChemistryAnswer disputed

   Which one of the following statements is correct?

   aLiquid sodium is employed as a coolant in nuclear reactorsbCalcium carbonate is an ingredient of toothpastecBordeaux mixture consists of sodium sulphate and limedZinc amalgams are used as a dental filling
5. Prelims 2003Q45Chemistry

   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?

   aOnly 1bOnly 2cBoth 1 and 2dNeither 1 nor 2
6. Prelims 2003Q98Chemistry

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

   aorientationbshapecsizedspin
7. Prelims 2003Q105Chemistry

   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.

   aBoth A and R are individually true and R is the correct explanation of AbBoth A and R are individually true but R is NOT the correct explanation of AcA is true but R is falsedA is false but R is true
8. Prelims 2003Q108Chemistry

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

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

   aBoth A and R are individually true and R is the correct explanation of AbBoth A and R are individually true but R is NOT the correct explanation of AcA is true but R is falsedA is false but R is true
9. Prelims 2003Q144Chemistry

   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?

   aOnly 1bOnly 2cBoth 1 and 2dNeither 1 nor 2
10. Prelims 2003Q145Chemistry

    Which one of the following statements is not correct?

    aThe presence of NaCl increases the rate of setting of Plaster of ParisbGypsum is added to the cement to slow down its rate of settingcAll alkaline earth metals form hydrated saltsdBarium and Strontium are found free in nature
11. Prelims 2002Q28Chemistry

    Which one of the following statements is not correct?

    aThe boiling point of an aqueous solution is higher than that of pure waterbAddition of solutes to a solution causes an increase in its water potentialcThe vapour pressure of the water in a solution is lower than that of pure waterdWhen a solution is separated from water by a semi permeable membrane, water movement can be prevented by applying pressure to the solution
12. Prelims 2002Q110Chemistry

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

    List I (Oxidation number)

    A.2

    B.3

    C.4

    D.6

    List II (The element)

    1.Oxidation number of Mn in MnO₂

    2.Oxidation number of S in H₂S₂O₇

    3.Oxidation number of Ca in CaO₂

    4.Oxidation number of Al in NaAlH₄

    aA-3, B-4, C-1, D-2bA-4, B-3, C-1, D-2cA-3, B-4, C-2, D-1dA-4, B-3, C-2, D-1
13. Prelims 2002Q145Chemistry

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

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

    aBoth A and R are individually true and R is the correct explanation of AbBoth A and R are individually true but R is not a correct explanation of AcA is true but R is falsedA is false but R is true
14. Prelims 2001Q116Chemistry

    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?

    aBoth A and R are individually true and R is the correct explanation of AbBoth A and R are individually true but R is NOT a correct explanation of AcA is true but R is falsedA is false but R is true
15. Prelims 2001Q117Chemistry

    Which one of the following is NOT radioactive?

    aAstatinebFranciumcTritiumdZirconium
16. Prelims 2001Q118Chemistry

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

    aMethane, ethane, propane and butanebPropane, butane, ethane and methanecButane, ethane, propane and methanedButane, propane, ethane and methane
17. Prelims 2001Q119Chemistry

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

    aAufbau principlebHeisenberg’s uncertainty principlecHund’s ruledPauli’s exclusion principle
18. Prelims 2001Q120Chemistry

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

    adialysisbelectrolysischydrolysisdphotolysis
19. Prelims 2001Q121Chemistry

    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?

    aI onlybII onlycI and IIIdII and III
20. Prelims 2000Q107Chemistry

    Most of the explosions in mines occur due to the mixing of

    ahydrogen with oxygenboxygen with acetylenecmethane with airdcarbon dioxide with ethane
21. Prelims 2000Q108Chemistry

    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:

    aI-A, II-B, III-D, IV-CbI-B, II-A, III-C, IV-DcI-A, II-B, III-C, IV-DdI-B, II-A, III-D, IV-C
22. Prelims 2000Q109Chemistry

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

    aCarborundumbTungstencCast irondNichrome
23. Prelims 2000Q110Chemistry

    Soft drinks such as colas contain significant quantities of

    acaffeinebnicotinectannindrenin
24. Prelims 2000Q111Chemistry

    Aluminium surfaces are often “anodized”. This means the deposition of a layer of

    achromium oxidebaluminium oxidecnickel oxidedzinc oxide
25. Prelims 2000Q112Chemistry

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

    akills bacteriabkills germs and sporescabsorbs moisturedabsorbs all gases present inside the bottle
26. Prelims 2000Q113Chemistry

    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:

    aI-C, II-B, III-A, IV-DbI-B, II-C, III-D, IV-AcI-B, II-C, III-A, IV-DdI-C, II-B, III-D, IV-A
27. Prelims 2000Q114ChemistryAnswer disputed

    Assertion (A): Large cold storage plants use ammonia as refrigerant while domestic refrigerators use chlorofluorocarbons.

    Reason (R): Ammonia can be liquified at ambient temperatures at low pressures.

    aBoth A and R are true, and R is the correct explanation of AbBoth A and R are true, but R is not a correct explanation of AcA is true, but R is falsedA is false, but R is true
28. Prelims 2000Q124Chemistry

    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?

    aI and IIIbII and IIIcI, II and IVdI, II, III and IV
29. Prelims 1999Q109Chemistry

    Match List I (Naturally occurring substances) with List II (Elements) and select the correct answer using the codes given below the Lists:

    List I

    I.Diamond

    II.Marble

    III.Sand

    IV.Ruby

    List II

    A) Calcium

    B) Silicon

    C) Aluminium

    D) Carbon

    Codes:

    aI-C, II-A, III-B, IV-DbI-D, II-B, III-A, IV-CcI-B, II-A, III-C, IV-DdI-D, II-A, III-B, IV-C
30. Prelims 1999Q122Chemistry

    When ants bite, they inject

    aglacial acetic acidbmethanolcformic aciddstearic acid