(i) → (e) Rosenmund’s reduction

(ii) → (d) Cannizaro’s reaction

(iii) → (a) Friedel Crafts acylation

(iv) → (b) HVZ reaction

(v) → (f) Stephen’s reaction

(vi) → (c) Aldol condensation

EXPLAINATION:

(i) The given reaction is known as Rosenmund’s reduction.

Acid chloride reacts with Pd-C/ BaSO₄ to form the corresponding aldehyde.

(ii) The given reaction is known as Cannizaro’s reaction.

Benzaldehyde undergoes self-oxidation and reduction reaction when heated with concentrated NaOH to form benzyl alcohol and sodium benzoate.

(iii) The given reaction is known as Friedel Crafts acylation reaction.

When benzene is treated with CH₃-CO-Cl in presence of anhydrous AlCl₃, acetophenone is formed.

(iv) The given reaction is known as the HVZ reaction.

Carboxylic acids having an α-hydrogen when treated with bromine in the presence of small amount of red phosphorus gives bromocarboxylic acids.

(v) The given reaction is known as Stephen’s reaction.

Here, nitriles are reduced to imine and then imine is hydrolyzed to the corresponding aldehyde.

(vi) The given reaction is known as Aldol condensation. Here, ethanol having one α-hydrogen atom undergoes a reaction in the presence of dilute NaOH to form 3-Hydroxybutanal and is further converted to but-2-enal.