JEE Main Salt Analysis Previous Year Questions with Solutions

Salt analysis previous year questions and solutions are given in this article. Salt analysis involves the identification of the cation and anion of an inorganic salt. This is done by conducting a series of tests systematically and using the observations to confirm the absence or presence of specific cations and anions. This is also known as systematic qualitative analysis or qualitative inorganic analysis. This is an analysis method used to determine the number of elements or molecules produced during a chemical reaction. Organic compounds comprise carbon, hydrogen, oxygen, nitrogen, phosphorus, sulphur and halogens. The various methods used for the measurement of percentage composition of elements in an organic compound are explained in the salt analysis.

The important topics include detection of C and H, test for Phosphorus, Liebig’s Combustion Method, Carius Method, estimation of Sulphur, estimation of Phosphorus, estimation of Nitrogen by Dumas Method, estimation of Nitrogen by Kjeldahl Method, estimation of Oxygen by Aluise’s method, etc. The questions given here give you an idea about what type of questions to expect from the topic salt analysis. BYJU’S provides solutions created by our subject expert team. Students can easily download these solutions in PDF form for free.

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JEE Main Previous Year Solved Questions on Salts Analysis

1. Copper wire test for halogens is known as:-

(1) Duma’s Test

(2) Beilstein’s Test

(3) Lasssigne’s Test

(4) Liebig’s Test

Solution:

Copper wire test for halogens is known as Beilstein’s Test.

Hence option (2) is the answer.

2. Beilstein test is used for estimation of which one of the following elements?

(1) S

(2) Cl

(3) C and H

(4) N

Solution:

The Beilstein test is a chemical test for organic halides. In the given options, Cl is in the halogen group.

Hence option (2) is the answer.

3. Which of the following statements about Na2O2 is not correct?

(1) Na2O2oxidises Cr3+ to CrO42- in acid medium

(2) It is diamagnetic in nature

(3) It is the superoxide of sodium

(4) It is a derivative of H2O2

Solution:

Na2O2 is the peroxide of sodium.

Hence option (3) is the answer.

4. Which of the following salts is the most basic in aqueous solution?

(1) CH3COOK

(2) FeCl3

(3) Pb(CH3 COO)2

(4) AlCN2

Solution:

CH3COOK + H2O → CH3COOH + KOH

KOH is a strong base and CH3COOH is a weak acid.

So the solution is basic in nature.

Hence option (1) is the answer.

5. Which one of the following exhibits the largest number of oxidation states?

(1) Mn(25)

(2) V(23)

(3) Cr (24)

(4) Ti (22)

Solution:

Mn can show 6 oxidation state from +2 to +7. It has 5 unpaired electrons in 3d orbitals and 2 electrons in 4s.

Hence option (1) is the answer.

6. The products obtained on heating LiNO3 will be:-

(1) LiNO2 + O2

(2) Li2O + NO2 + O2

(3) Li3N + O2

(4) Li2O + NO + O2

Solution:

On heating lithium nitrate, lithium oxide and nitrogen dioxide are obtained.

LiNO3 → Li2O + NO2 + O

Hence option (2) is the answer.

7. Fire extinguishers contain H2SO4 and which one of the following:-

(1) CaCO3

(2) NaHCO3 and Na2CO3

(3) Na2CO3

(4) NaHCO3

Solution:

Fire extinguishers contain H2SO4 and NaHCO3.

Hence option (4) is the answer.

8. Potassium dichromate when heated with concentrated sulphuric acid and a soluble chloride, gives brown-red vapours of:

(1) CrO3

(2) Cr2O3

(3) CrCl3

(4) CrO2Cl2

Solution:

When potassium dichromate is heated with concentrated H2SO4 and a soluble chloride, brownish-red vapours of chromyl chloride is formed.

K2Cr2O7 + conc. H2SO4 + Cl → CrO2Cl2

Hence option (4) is the answer.

9. Identify incorrect statement

(1) Copper (I) compounds are colourless except where colour results from charge transfer

(2) Copper (I) compounds are diamagnetic

(3) Cu2S is black

(4) Cu2O is colourless

Solution:

Cuprous oxide, Cu2O is red in colour. So statement 4 is wrong.

Hence option (4) is the answer.

10. How many electrons are involved in the following redox reaction?

Cr2O72- + Fe2+ + C2O42- → Cr3+ + Fe3+ + CO2 (unbalanced)

(1) 3

(2) 4

(3) 5

(4) 6

Solution:

Cr2O72- + 2Fe2+ + 2C2O42- → 2Cr3+ + 2Fe3+ + 4CO2

6 electrons are involved in this reaction.

Hence option (4) is the answer.

11. The correct statement for the molecule, CsI3 is:

(1) it contains Cs3+ and I ions

(2) it contains Cs3+ and I+ ions

(3) it is a covalent molecule

(4) it contains Cs3+ and I3 ions

Solution:

CsI3 → Cs+ + I3

Hence option (4) is the answer.

12. Copper becomes green when exposed to moist air for a long period. This is due to:-

(1) the formation of a layer of cupric oxide on the surface of copper.

(2) the formation of basic copper sulphate layer on the surface of the metal

(3) the formation of a layer of cupric hydroxide on the surface of copper.

(4) the formation of a layer of basic carbonate of copper on the surface of copper.

Solution:

When exposed to air, Copper metal turns green in colour because of corrosion. The metal reacts with moisture and atmospheric gases to form a mixture of copper carbonate and copper hydroxide.

Hence option (4) is the answer.

13. Which of the following statements is incorrect?

(1) Fe2+ ion also gives blood red colour with SCN ion

(2) Cupric ion reacts with an excess of ammonia solution to give a deep blue colour of [Cu(NH3)4]2+ ion.

(3) Fe3+ ion gives blood red colour with SCN ion.

(4) On passing H2S into Na2ZnO2 solution, a white ppt of ZnS is formed.

Solution:

Only Fe3+ ions give a blood-red colour with SCN ions. So statement (1) is wrong.

Hence option (1) is the answer.

14. Amongst the following, identify the species with an atom in +6 oxidation state:

(1) [MnO4]

(2) [Cr(CN)6]3-

(3) Cr2O3

(4) CrO2Cl2

Solution:

Oxidation state of Cr in CrO2Cl2 is +6.

Hence option (4) is the answer.

15. Which one of the following cannot function as an oxidising agent?

(1) NO3(aq)

( 2) I

(3) Cr2O72-

( 4) S(S)

Solution:

I has lowest oxidation state. It can act as a strong reducing agent.

Hence option (2) is the answer.

Also Read:- Qualitative Analysis of Organic Compounds