NEET UG - Detection of elements and functional groups hydroxyl carbonyl carboxyl and amino groups in organic compounds Online Test (MCQ Quiz)

1. Which test is commonly used for the qualitative detection of nitrogen, sulfur, and halogens in organic compounds?

A) Liebig's method B) Dumas method C) Sodium fusion test D) Kjeldahl's method

2. In the sodium fusion test for detecting elements in organic compounds, what is the fused mixture heated with?

A) Dilute sulfuric acid B) Distilled water C) Dilute hydrochloric acid D) Ferrous sulfate solution

3. When testing for nitrogen using the sodium fusion test, the sodium cyanide formed reacts with ferrous sulfate to produce:

A) Sodium ferrocyanide B) Sodium ferricyanide C) Sodium nitroprusside D) Ammonia

4. A Prussian blue coloration in the sodium fusion test for nitrogen indicates the presence of:

A) Sulfur B) Halogens C) Nitrogen D) Phosphorus

5. How is the presence of sulfur detected in the sodium fusion test?

A) Formation of a yellow precipitate with sodium nitroprusside B) Formation of a green precipitate with ferrous sulfate C) Formation of a violet color with sodium nitroprusside D) Formation of a red precipitate with lead acetate

6. If both nitrogen and sulfur are present in an organic compound, the sodium fusion test will yield a precipitate that is:

A) Blue B) Green C) Black D) Red

7. For the detection of halogens using the sodium fusion test, the sodium halide is dissolved in water and then treated with:

A) Potassium permanganate B) Silver nitrate solution C) Barium chloride solution D) Ammonium hydroxide

8. A white precipitate, soluble in ammonium hydroxide, formed during the halogen test (sodium fusion) indicates the presence of:

A) Iodine B) Bromine C) Chlorine D) Fluorine

9. A pale yellow precipitate, sparingly soluble in ammonium hydroxide, in the halogen test indicates:

A) Chlorine B) Bromine C) Iodine D) Fluorine

10. A yellow precipitate, insoluble in ammonium hydroxide, in the halogen test signifies the presence of:

A) Chlorine B) Bromine C) Iodine D) Fluorine

11. Which reagent is used to detect the presence of a hydroxyl (-OH) group in an organic compound through esterification?

A) Lucas reagent B) Tollens' reagent C) Fehling's solution D) Acetic anhydride or acetyl chloride

12. Lucas reagent is a solution of anhydrous zinc chloride in concentrated hydrochloric acid, primarily used to distinguish between:

A) Primary and secondary alcohols B) Secondary and tertiary alcohols C) Primary, secondary, and tertiary alcohols D) Alcohols and phenols

13. Which type of alcohol reacts instantaneously with Lucas reagent to produce turbidity?

A) Primary alcohol B) Secondary alcohol C) Tertiary alcohol D) Phenol

14. A cloudy solution that clears up on warming and becomes turbid on cooling is characteristic of the reaction of Lucas reagent with which type of alcohol?

A) Primary alcohol B) Secondary alcohol C) Tertiary alcohol D) Phenol

15. Primary alcohols react with Lucas reagent after a considerable delay or do not react at room temperature, showing turbidity only upon heating. This is because:

A) They form stable carbocations B) They form unstable carbocations C) They undergo SN1 reaction rapidly D) They undergo SN2 reaction rapidly

16. Phenols react with Lucas reagent to give turbidity:

A) Immediately B) After a few minutes C) On heating D) Not at all

17. Which functional group is characterized by the presence of a carbonyl group (C=O) bonded to two carbon atoms?

A) Aldehyde B) Ketone C) Carboxylic acid D) Ester

18. Tollens' reagent is used to test for the presence of:

A) Ketones B) Carboxylic acids C) Aldehydes D) Esters

19. When Tollens' reagent reacts with an aldehyde, it forms a silver mirror on the inner walls of the test tube. This is due to the oxidation of the aldehyde to a:

A) Ketone B) Carboxylic acid C) Alcohol D) Ester

20. Which of the following compounds will give a positive test with Tollens' reagent?

A) Acetone B) Benzaldehyde C) Acetic acid D) Ethyl acetate

21. Fehling's solution is another reagent used to test for aldehydes. It is a mixture of:

A) Aqueous solution of silver nitrate and dilute nitric acid B) Aqueous solution of potassium hydroxide and alkaline copper sulfate C) Solution of anhydrous zinc chloride and concentrated HCl D) Solution of sodium nitroprusside and sodium hydroxide

22. A positive test with Fehling's solution (which consists of Fehling's solution A and B) results in the formation of a precipitate of:

A) Silver B) Copper(I) oxide C) Copper(II) oxide D) Cuprous chloride

23. Which type of aldehyde reacts with Fehling's solution to give a positive test?

A) Aliphatic aldehydes B) Aromatic aldehydes (except those with electron-donating groups) C) Both aliphatic and aromatic aldehydes D) Only aromatic aldehydes

24. Ketones do not react with Tollens' reagent or Fehling's solution because:

A) They are already in a higher oxidation state B) They lack the alpha-hydrogen atom necessary for oxidation C) Their carbonyl carbon is not sufficiently electrophilic D) They are resistant to nucleophilic attack

25. The sodium salt of a carboxylic acid can be prepared by reacting the acid with:

A) Acidic reagents B) Basic reagents C) Neutral reagents D) Oxidizing agents

26. Which test can be used to differentiate between aldehydes and ketones?

A) Lucas test B) Tollens' test C) Sodium fusion test D) Victor Meyer test

27. The functional group -COOH characterizes which class of organic compounds?

A) Alcohols B) Aldehydes C) Ketones D) Carboxylic acids

28. Carboxylic acids can be detected by their reaction with sodium bicarbonate, which produces:

A) Hydrogen gas B) Carbon dioxide gas C) Oxygen gas D) Nitrogen gas

29. The evolution of effervescence (bubbling) when an organic compound is treated with sodium bicarbonate solution is a strong indication of the presence of a:

A) Hydroxyl group B) Amino group C) Carboxylic acid group D) Carbonyl group

30. Which of the following compounds will give effervescence with sodium bicarbonate?

A) Ethanol B) Acetone C) Acetic acid D) Aniline

31. The presence of an amino group (-NH2) in an organic compound can be detected using:

A) Fehling's solution B) Tollens' reagent C) Nitrous acid D) Potassium permanganate

32. Primary amines react with nitrous acid (HNO2) to form:

A) Diazonium salts B) Nitrosoamines C) Alcohols and nitrogen gas D) Amides

33. Which of the following will produce nitrogen gas when treated with nitrous acid?

A) Secondary amine B) Tertiary amine C) Primary aliphatic amine D) Ammonia

34. Secondary amines react with nitrous acid to form:

A) Alcohols B) Nitrosoamines C) Diazonium salts D) Amides

35. Tertiary amines react with nitrous acid to form:

A) Alcohols and nitrogen gas B) Nitrosoamines C) Salts of amines D) Amides

36. The carbylamine test is used to detect the presence of:

A) Primary alcohols B) Secondary amines C) Primary amines D) Tertiary amines

37. In the carbylamine test, a foul-smelling isocyanide is formed when primary amines are heated with:

A) Chloroform and alcoholic KOH B) Ethanol and concentrated H2SO4 C) Sodium and liquid ammonia D) Tollens' reagent

38. Secondary and tertiary amines do not give the carbylamine test because:

A) They do not contain a replaceable hydrogen atom on the nitrogen B) They are not basic enough C) They react too slowly D) They form stable complexes

39. Which functional group is responsible for the characteristic reactions of phenols with ferric chloride, producing a colored complex?

A) Alcohol (-OH) B) Ether (-O-) C) Phenolic -OH D) Aldehyde (-CHO)

40. Phenols typically produce a color with neutral ferric chloride solution. The color observed can be:

A) Yellow B) Green, blue, or violet C) Red D) Brown

41. The reaction of an alcohol with acetyl chloride or acetic anhydride is a test for the presence of the hydroxyl group, forming an ester. This reaction is an example of:

A) Oxidation B) Reduction C) Esterification D) Hydrolysis

42. Which of the following reagents can be used to detect the presence of a carbonyl group (C=O) in general (aldehydes and ketones)?

A) 2,4-Dinitrophenylhydrazine B) Sodium bicarbonate C) Lucas reagent D) Potassium permanganate

43. 2,4-Dinitrophenylhydrazine reacts with both aldehydes and ketones to form characteristic crystalline precipitates known as:

A) Oximes B) Hydrazones C) Semicarbazones D) Dinitrophenylhydrazones

44. The melting point of the derivative formed with 2,4-Dinitrophenylhydrazine can help in identifying a specific aldehyde or ketone because:

A) All derivatives have the same melting point B) Each derivative has a unique melting point C) Melting point is irrelevant for identification D) Melting point is only useful for solids

45. Which test is specifically used to distinguish between aldehydes and alpha-hydroxy ketones, as both can reduce Tollens' reagent?

A) Fehling's test B) Benedict's test C) Sodium nitroprusside test D) Iodoform test

46. The iodoform test is positive for compounds containing the CH3-CO- group or CH3-CH(OH)- group. This test involves reaction with:

A) Iodine and sodium hydroxide B) Iodine and dilute acid C) Iodine and potassium iodide D) Iodine monochloride

47. A positive iodoform test is indicated by the formation of a yellow precipitate of:

A) Iodine B) Iodoform (CHI3) C) Sodium iodide D) Potassium iodide

48. Which of the following compounds will give a positive iodoform test?

A) Methanol B) Ethanol C) Propan-1-ol D) Propan-2-ol

49. Which of the following compounds will give a positive iodoform test?

A) Propanone B) Butanone C) Pentane D) Hexane

Detection of elements and functional groups hydroxyl carbonyl carboxyl and amino groups in organic compounds - Online Test

Test Results