How do you convert the following? Ethanal to Ethane
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Solution and Explanation
Complete reduction of an aldehyde group down to an alkane.
Step 2: Meaning
The carbonyl oxygen is completely removed and replaced by two hydrogen atoms.
Step 3: Analysis
This requires specific strong reductive methods, such as the Clemmensen reduction using Zinc amalgam and concentrated $HCl$, or the Wolff-Kishner reduction using hydrazine and KOH.
Final Answer: By Clemmensen reduction (using zinc amalgam and concentrated $HCl$). $CH_3-CHO + 4[H] \xrightarrow{Zn-Hg / \text{conc. } HCl} CH_3-CH_3 + H_2O$
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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
(iv) (CH3 )3CNH2 (v) C6H5NHCH3 (vi) (CH3CH2 )2NCH3 (vii) m–BrC6H4NH2
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.
(iv) Although amino group is o– and p– directing in aromatic electrophilic substitution reactions, aniline on nitration gives a substantial amount of m-nitroaniline.
(v) Aniline does not undergo Friedel-Crafts reaction.
(vi) Diazonium salts of aromatic amines are more stable than those of aliphatic amines. (vii) Gabriel phthalimide synthesis is preferred for synthesising primary amines.
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