NEET UG - Chemistry involved in preparation of inorganic and organic compounds and titrimetric and qualitative salt analysis experiments Question Bank with Options

1. In the preparation of hydrogen gas by the reaction of zinc with dilute sulfuric acid, the acid is usually added slowly to:

A) Control the rate of reaction and prevent excessive foaming

B) Increase the yield of hydrogen gas

C) Ensure complete reaction of the zinc

D) Decrease the temperature of the reaction

2. Which of the following is a characteristic test for detecting the presence of starch?

A) Fehling's solution

B) Tollens' reagent

C) Iodine solution

D) Benedict's solution

3. The preparation of aniline from nitrobenzene using Sn/HCl is a specific type of:

A) Oxidation

B) Reduction

C) Substitution

D) Addition

4. In the qualitative analysis of anions, what is the purpose of adding dilute HCl or H2SO4 before adding BaCl2?

A) To precipitate the anion

B) To ensure that only the desired anion precipitates and to avoid interference from other anions that form insoluble barium salts (e.g., carbonates, sulfites)

C) To act as a catalyst

D) To neutralize any basic impurities

5. Which apparatus is used for accurately measuring and delivering variable amounts of liquid, typically in a laboratory preparation?

A) Volumetric flask

B) Pipette

C) Burette

D) Graduated cylinder

6. The preparation of ethyl chloride from ethanol and thionyl chloride is preferred because:

A) It is a very slow reaction

B) The byproducts HCl and SO2 are gaseous and easily removed

C) It requires a strong oxidizing agent

D) It results in the formation of alkenes

7. Which gas is produced when a nitrate salt is heated strongly with copper turnings and concentrated sulfuric acid?

A) Nitric oxide (NO)

B) Nitrogen dioxide (NO2)

C) Ammonia (NH3)

D) Nitrous oxide (N2O)

8. What is the principle of gravimetric analysis?

A) Measuring the volume of a solution of known concentration required to react completely with the analyte

B) Measuring the mass of a pure solid element or compound that is equivalent to the analyte

C) Measuring the change in color to determine concentration

D) Measuring the evolution of gas

9. In the preparation of nitric acid from potassium nitrate and concentrated sulfuric acid, what is the role of concentrated sulfuric acid?

A) As a catalyst

B) As a dehydrating agent and reactant

C) As a solvent

D) To absorb the evolved gas

10. Which method is commonly used for the purification of solid organic compounds?

A) Distillation

B) Sublimation

C) Crystallisation

D) Chromatography

11. The 'Beilstein test' is used to detect the presence of which element in an organic compound?

A) Sulfur

B) Nitrogen

C) Halogens

D) Phosphorus

12. Which substance is used as a primary standard in acid-base titrations?

A) Sodium hydroxide

B) Hydrochloric acid

C) Potassium permanganate

D) Anhydrous sodium carbonate

13. What is the purpose of adding dilute HCl to the salt solution before precipitating Group II cations with H2S?

A) To increase the solubility of the sulfides

B) To ensure that only Group II cations precipitate as sulfides and not those of Group III

C) To act as a catalyst

D) To prevent the precipitation of hydroxides

14. The preparation of an ether from two molecules of an alcohol in the presence of concentrated sulfuric acid at a specific temperature is an example of:

A) Dehydration (intermolecular)

B) Dehydration (intramolecular)

C) Oxidation

D) Reduction

15. In the analysis of cations, Group V usually contains which ion?

A) Fe^3+

B) Al^3+

C) Ba^2+

D) NH4^+

16. The titration of a weak base with a strong acid requires an indicator that changes color in which pH range?

A) Acidic range (pH < 7)

B) Neutral range (pH ≈ 7)

C) Alkaline range (pH > 7)

D) The indicator choice is not critical

17. Which apparatus is used to heat a solution and allow controlled evaporation?

A) Beaker

B) Crucible

C) Evaporating dish

D) Watch glass

18. What is the primary purpose of the 'Sodium Fusion Test' in organic qualitative analysis?

A) To determine the boiling point of the compound

B) To convert inorganic elements present in the organic compound into ionic form for easier detection

C) To measure the molecular weight

D) To identify functional groups

19. The preparation of 'soap' from fats or oils and a strong base is called:

A) Esterification

B) Hydrolysis

C) Saponification

D) Neutralization

20. Which test is used to detect the presence of chlorides, bromides, or iodides by forming a precipitate with silver nitrate?

A) Flame test

B) Beilstein test

C) Silver nitrate test

D) Sodium fusion test

21. The endpoint of a titration is the point at which:

A) The reaction is complete

B) The indicator changes color

C) The titrant is exactly equivalent to the analyte

D) The solution becomes saturated

22. In the preparation of ammonia gas, drying is typically done using:

A) Concentrated sulfuric acid

B) Anhydrous calcium chloride

C) Phosphorus pentoxide

D) Quicklime (CaO)

23. Which of the following is a common method for preparing esters in the laboratory?

A) Oxidation of alcohols

B) Reduction of aldehydes

C) Fischer esterification

D) Hydrolysis of amides

24. Why is it important to wash the precipitate in gravimetric analysis?

A) To increase the amount of precipitate

B) To remove soluble impurities adhering to the precipitate

C) To speed up the drying process

D) To convert the precipitate into a more stable form

25. What is the characteristic flame coloration for sodium ions (Na+)?

A) Crimson red

B) Golden yellow

C) Lilac

D) Apple green

26. The preparation of an aldehyde from a primary alcohol using PCC (Pyridinium Chlorochromate) is an example of:

A) Reduction

B) Oxidation

C) Hydrolysis

D) Substitution

27. The 'borax bead test' is primarily used to detect the presence of which type of elements?

A) Alkali metals

B) Alkaline earth metals

C) Transition metals

D) Halogens

28. Which of the following is an example of a redox titration?

A) Acid-base titration

B) Precipitation titration

C) Complexometric titration

D) Permanganometric titration

29. What is the purpose of the Group Separation scheme in qualitative analysis?

A) To precipitate all cations at once

B) To systematically separate cations into different groups based on their properties with specific reagents

C) To determine the concentration of anions

D) To identify volatile compounds

30. The preparation of an alkyl halide from an alcohol using SOCl2 is advantageous because:

A) It is a slow reaction

B) The byproducts (SO2 and HCl) are gases and easily removed

C) It requires a strong oxidizing agent

D) It leads to elimination products

31. Which reagent is used to detect the presence of phosphate ions (PO4^3-) by forming a yellow precipitate?

A) Ammonium molybdate in nitric acid

B) Barium chloride

C) Silver nitrate

D) Potassium ferrocyanide

32. In a titration, the solution of known concentration is called the:

A) Analyte

B) Titrant

C) Indicator

D) Buffer

33. What is the principle behind qualitative salt analysis?

A) Selective precipitation of ions

B) Changes in color upon heating

C) Gas evolution upon reaction with acids

D) Formation of insoluble salts

34. Which of the following is a primary alcohol?

A) Ethanol

B) Isopropanol

C) Tert-butanol

D) 2-Propanol

35. The preparation of an ester from a carboxylic acid and an alcohol is known as:

A) Hydrolysis

B) Saponification

C) Fischer esterification

D) Oxidation

36. In the detection of ammonium ions (NH4^+), adding a strong base like NaOH and heating results in the evolution of which gas?

A) Hydrogen

B) Ammonia

C) Nitrogen

D) Oxygen

37. For the titration of a weak acid with a strong base, which indicator is most suitable?

A) Methyl orange

B) Methyl red

C) Phenolphthalein

D) Bromothymol blue

38. What is the purpose of heating the salt solution with sodium carbonate in the preparation of insoluble salts?

A) To increase solubility

B) To precipitate the cation as a carbonate

C) To remove interfering anions

D) To speed up the reaction

39. The preparation of ethyl bromide from ethanol and hydrobromic acid is an example of:

A) Nucleophilic substitution

B) Electrophilic substitution

C) Addition reaction

D) Elimination reaction

40. Which of the following is a characteristic observation for the presence of nitrate ions (NO3^-) in the ring test?

A) Brown ring at the interface of the two layers

B) Green flame test

C) White precipitate with AgNO3

D) Effervescence with dilute acid

41. What is the primary function of an indicator in a titration?

A) To increase the solubility of the analyte

B) To provide a visual signal for the endpoint

C) To act as a titrant

D) To standardize the solution

42. In the preparation of aniline from nitrobenzene, which reducing agent is commonly employed?

A) Sodium borohydride

B) Lithium aluminum hydride

C) Tin (Sn) or Iron (Fe) in the presence of HCl

D) Hydrogen gas with a catalyst (e.g., Pt, Pd)

43. The Lassaigne's test is used to detect the presence of which elements in an organic compound?

A) Carbon and Hydrogen

B) Oxygen and Nitrogen

C) Halogens, Nitrogen, and Sulfur

D) Phosphorus and Sulfur

44. When testing for sulfate ions (SO4^2-), why is dilute hydrochloric acid added before barium chloride solution?

A) To increase the solubility of barium sulfate

B) To prevent the precipitation of other interfering anions like sulfites and carbonates

C) To act as a catalyst

D) To neutralize the sulfate ions

45. Which indicator is typically used for the titration of a strong acid with a strong base?

A) Phenolphthalein

B) Methyl orange

C) Bromothymol blue

D) All of the above

46. In the preparation of ethyl acetate, what is the role of concentrated sulfuric acid?

A) As a reactant

B) As a catalyst and dehydrating agent

C) As a solvent

D) To neutralize the product

47. The preparation of aspirin from salicylic acid and acetic anhydride is an example of which type of organic reaction?

A) Addition reaction

B) Elimination reaction

C) Substitution reaction

D) Esterification

48. Which reagent is commonly used to detect the presence of carbonate ions (CO3^2-) in a salt sample?

A) Barium chloride solution

B) Ammonium hydroxide solution

C) Dilute hydrochloric acid

D) Potassium permanganate solution

49. In qualitative salt analysis, what is the purpose of the dry test?

A) To determine the exact concentration of ions

B) To detect the presence of volatile radicals or characteristic properties

C) To precipitate all cations simultaneously

D) To measure the pH of the solution

50. Which apparatus is typically used for accurate measurement of liquid volumes in titrations?

A) Beaker

B) Conical flask

C) Burette

D) Measuring cylinder

Chemistry involved in preparation of inorganic and organic compounds and titrimetric and qualitative salt analysis experiments - Question Bank