Show how each of the following compounds can be converted to benzoic acid: (I) Acetophenone; (II) Ethyl benzene.
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Solution and Explanation
Answer:
(I) Acetophenone (C6H5-CO-CH3): On strong oxidation with alkaline KMnO4 followed by acidification (H3O+), the -CO-CH3 side chain is oxidised and the extra carbons are lost, giving benzoic acid C6H5-COOH.
(II) Ethyl benzene (C6H5-CH2-CH3): The whole ethyl side chain is oxidised by hot alkaline KMnO4 (then acidified). Because the carbon attached to the ring has benzylic hydrogens, the entire side chain is converted to a single -COOH group, giving benzoic acid C6H5-COOH.
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Write IUPAC names of the following compounds and classify them into primary, secondary and tertiary amines.
(i) (CH3 )2CHNH2 (ii) CH3 (CH2 )2NH2 (iii) CH3NHCH(CH3 )2
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Give one chemical test to distinguish between the following pairs of compounds.
(i) Methylamine and dimethylamine
(ii) Secondary and tertiary amines
(iii) Ethylamine and aniline
(iv) Aniline and benzylamine
(v) Aniline and N-methylanilineAccount for the following:
(i) pKb of aniline is more than that of methylamine.
(ii) Ethylamine is soluble in water whereas aniline is not.
(iii) Methylamine in water reacts with ferric chloride to precipitate hydrated ferric oxide.
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What is meant by the following terms? Give an example of the reaction in each case.
\((i)\)\(Cyanohydrin\)
\((ii)Acetal \)
\((iii)Semicarbazone \)
\((iv)Aldol \)
\((v)Hemiacetal \)
\((vi)Oxime \)
\((vii)Ketal \)
\((vii)Imine \)
\((ix)\)\(2,4-DNP-derivative \)
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\((iii) CH_3CH=CHCHO \)
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\((v) CH_3CH(CH_3)CH_2C(CH_3)_2COCH_3 \)
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\((vii) OHCC_6H_4CHO-p\)Write the IUPAC names of the following ketones and aldehydes. Wherever possible, give also common names.
\((i) CH_3CO(CH_2)_4CH_3 \)
\((ii) CH_3CH_2CHBrCH_2CH(CH_3)CHO \)
\((iii) CH_3(CH_2)_5CHO \)
\((iv) Ph-CH=CH-CHO\)
\((v)\)
\((vi) PhCOPh\)Draw structures of the following derivatives.
(i)The 2,4-dinitrophenylhydrazone of benzaldehyde
(ii)Cyclopropanone oxime
(iii)Acetaldehydedimethylacetal
(iv)The semicarbazone of cyclobutanone
(v)The ethylene ketal of hexan-3-one
(vi)The methyl hemiacetal of formaldehydePredict the products formed when cyclohexanecarbaldehyde reacts with following reagents.
(i)\(PhMgBr\) and then \(H3O + \)
(ii)Tollens' reagent
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(iv)Excess ethanol and acid
(v) Zinc amalgam and dilute hydrochloric acid
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