The acid formed when propyl magnesium bromide is treated with CO_2 followed by acid hydrolysis is:
C_3H_7OH
Propyl magnesium bromide is a Grignard reagent that reacts with carbon dioxide (CO2) to form a carboxylate anion. This anion is then hydrolyzed to form a carboxylic acid. The reaction can be summarized as follows:
RMgBr + CO2 → RCO− + MgBr+
Upon hydrolysis, the carboxylate anion is converted into a carboxylic acid:
RCO− + H2O → RCOOH
Thus, the acid formed is propionic acid (C3H7COOH), corresponding to option (A).
Propionic acid is the correct product of this Grignard reaction with CO2.
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-methylaniline
Account 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.