Class 12 Chemistry

Magical Series Assignment – W4.AU.10

Find the Compounds

 

Q.1.       An organic compound contains 69.77% carbon, 11.63% hydrogen and the rest is oxygen. The molecular mass of the compound is 86. It does not reduce Tollen's reagent but forms an addition compound with sodium hydrogen sulphite and gives a positive iodoform test. On vigorous oxidation it gives ethanoic and propanoic acids. Deduce the possible structure of the organic compound.

Q.2.       A compound A (C₂H₆O) on oxidation by PCC gave B, which on treatment with aqueous alkali and subsequent heating furnished C. B on oxidation by KMnO₄ forms a monobasic carboxylic acid with molar mass 60 g mol^–1. Deduce the structures of A, B and C.

Q.3.       An organic compound (A) on treatment with acetic acid in the presence of sulphuric acid produces an ester (B). (A) on mild oxidation gives (C). (C) with 50% KOH followed by acidification with dil. HCl generates (A) and (D). (D) with PCl₅ followed by reaction with ammonia gives (E). (E) on dehydration produces hydrocyanic acid. Identify the compounds (A), (B), (C), (D), and (E).

Q.4.       Compound A (C₇H₆Cl₂) on treatment with NaOH solution gives another compound B (C₇H₆O). B, on oxidation gives an acid C (C₇H₆O₂) which on treatment with a mixture of concentrated HNO₃ and H₂SO₄ gives a compound D (C₇H₅NO₄). B on treatment with conc. NaOH gives a compound E (C₇H₈O) and C₆H₅COONa. Deduce the structures of A, B, C, D and E.

Q.5.       An organic compound A (C₃H₆O) is susceptible to oxidation and forms compound B (C₃H₈O) on reduction. B reacts with HBr to form the compound C. C with Mg forms Grignard reagent D which reacts with A to form a product which on hydrolysis gives E. Identify A to E.

Q.6.       A ketone A (C₄H₈O), which undergoes a haloform reaction, gives compound B on reduction. B on heating with sulphuric acid gives a compound C which forms mono-ozonide D. D on hydrolysis in presence of Zn dust gives only acetaldehyde E. Identify A, B, C, D and E. Write the reactions involved.

Q.7.       An organic compound with molecular formula C₉H₁₀O forms 2, 4-DNP derivative, reduces Tollen's reagent and undergoes Cannizzaro's 'reaction. On vigorous oxidation it gives benzene-1, 2- dicarboxylic acid. Identify the compound.

Q.8.       An organic compound A, having the formula C₃H₈O on treatment with copper at 573 K, gives B. B does not reduce Fehling solution but gives a yellow precipitate of the compound C with I₂/NaOH. Deduce the structures of A, B and C.

Q.9.       An organic compound 'A' which has characteristic odour on treatment with NaOH forms two compounds 'B' and 'C'. Compound 'B' has the molecular formula C₇H₈O which on oxidation with CrO₃ gives back compound 'A'. Compound 'C' is the sodium salt of the acid. 'C' when heated with soda lime yields an aromatic hydrocarbon 'D'. Deduce the structures of A, B, C and D.

Q.10.   Compound (A), C₆H₁₂O₂ on reduction with LiAlH₄ yields two compounds (B) and (C). The compound (B) on oxidation gave (D) which on treatment with aqueous alkali and subsequent heating furnished (E). The latter on catalytic hydrogenation gave (C). The compound (D) on further oxidation gave CH₃COOH. Deduce the structures of (A), (B), (C), (D) and (E).

Q.11.   An organic compound (A), molecular formula C₈H₁₆O₂, was hydrolysed with dilute sulphuric acid to give a carboxylic acid (B) and an alcohol (C). Oxidation of (C) with chromic acid produced (B). (C) on dehydration gives but-1-ene. Write chemical equations for the reactions involved.

Q.12.   An organic compound (A) with molecular formula C₈H₈O forms an orange red precipitate with DNP reagent and gives yellow precipitate on heating with 12 and NaOH. It neither reduces Tollen's reagent nor Fehling reagent nor does it decolorize bromine water or Baeyer's reagent. On drastic oxidation with chromic acid, it gives a carboxylic acid. (B) having molecular formula C₇H₆O₂. Identify the compounds (A) and (B) and explain the reactions involved.

Q.13.   An organic compound (A) on treatment with ethyl alcohol gives a carboxylic acid (B) and compound (C). Hydrolysis of (C) under acidified conditions gives (B) and (D). Oxidation of (D) with KMnO₄ also gives (B). (B) on heating with Ca(OH)₂ gives (E) having molecular formula C₃H₆O. (E) does not give Tollen's test and does not reduce Fehling solution but forms a 2, 4-dinitrophenylhydrazone. Identify (A), (B), (C), (D) and (E).

Q.14.   Two moles of an organic compound 'A' on treatment with a strong base gives two compounds 'B' and ' C '. Compound 'B' on dehydrogenation with Cu gives 'A' while acidification of 'C' yields carboxylic acid 'D' with molecular formula of CH₂O₂. Identity the compounds A, B, C and D and write all chemical reactions involved.

 

Answers

Ans.1.              CH₃CH₂CH₂COCH₃

Ans.2.              A: CH₃CH₂OH

B: CH₃CHO

C: CH₃CH=CHCHO

Ans.3.              A: CH₃OH

B: CH₃COOCH₃

C: HCHO
D: HCOOH

E: HCONH₂ (methanamide)

Ans.4.              A: C₆H₅CHCl₂

B: C₆H₅CHO

C: C₆H₅COOH,
D: m-nitrobenzoic acid

E: C₆H₅CH₂OH

Ans.5.              A: CH₃CH₂CHO

B: CH₃CH₂CH₂OH

C: CH₃CH₂CH₂Br
D: CH₃CH₂CH₂MgBr

E: CH₃CH₂CH(OH)CH₂CH₂CH₃

Ans.6.              A: CH₃CH₂COCH₃

B: CH₃CH₂CH(OH)CH₃

C: CH₃CH=CHCH₃
D: Ozonide

E: CH₃CHO

Ans.7.              2-Ethyulbenzaldehyde

Ans.8.              A: CH₃CH(OH)CH₃

B: CH₃COCH₃

C: CHI₃

Ans.9.              A: C₆H₅CHO

B: C₆H₅CH₂OH

C: C₆H₅COONa
D: C₆H₆

Ans.10.          A: CH₃CH₂CH₂COOCH₂CH₃ or CH₃COOCH₂CH₂CH₂CH₃
B: CH₃CH₂OH

C: CH₃CH₂CH₂CH₂OH
D: CH₃CHO

E: CH₃CH=CHCHO (Crotonaldehyde)

Ans.11.           

Ans.12.          A: C₆H₅COCH₃

B: C₆H₅COOH

Ans.13.          A: (CH₃CO)₂O (Acetic anhydride)
B: CH₃COOH

C: CH₃COOCH₂CH₃

D: CH₃CH₂OH

E: CH₃COCH₃

Ans.14.          A: HCHO

B: CH₃OH

C: HCOONa
D: HCOOH

 

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