How will you obtain propan-2-ol from grignard’s reagent ? (Give balanced chemical equations).

Propan −2−ol is a secondary alcohol with three carbon atoms. Hence, along with CH 3 MgBr we should use an aldehyde having two carbon atoms, that is, ethanal and follow it up with hydrolysis.

Identify the compounds A, B, C and D in the given reaction:

Hydration of acetylene (followed by keto enol tautomerism) gives acetaldehdye. This is followed by oxidation to form acetic acid. The reaction of acetic acid and calcium hydroxide produces calcium acetate which on dry distillation gives acetone and calcium carbonate. CH ≡ CH → Hg + 2 / H 2 SO 4 H 2 O CH 3 CHO → K 2 Cr 2 O 7 + H 2 SO 4 O CH 3 COOH → Ca OH 2 CH 3 COO 2 Ca → dry distillation ∆ CH 3 COCH 3 A – CH 3 CHO , Acetaldehyde B – CH 3 COOH , Acetic acid C – ( CH 3 COO ) 2 Ca , Calcium acetate D – CH 3 COCH 3 , Acetone

Identify the compounds A, B, C and D.

In this reaction sequence, benzoic acid is treated with thionyl chloride produces benzoyl chloride which on ammonolysis form benzamide. The benzamide undergoes bromination in presence of potassium hydroxide which forms aniline. The aniline produce benzene diazonium chloride when reacting with sodamide and hydrochloric acid. Thus, the compound A is benzoyl chloride, B is benzamide and C will be aniline. Then, the compound D is benzene diazonium chloride. The reaction is given below, C 6 H 5 COOH → SOCl 2 C 6 H 5 COCl A → NH 3 C 6 H 5 CONH 2 B → Br 2 / KOH C 6 H 5 NH 2 C → 0 - 5 ° C NaNO 2 + HCl C 6 H 5 N 2 + Cl - D .

Explain why acetic acid is a weaker acid as compared to formic acid.

Acetic acid has electron donating methyl group attached to - COOH group that shows positive inductive effect and increases the electron density on the carbon atom of - COOH group, which reduces the acidity of acid. But, in case of formic acid, HCOOH no such electron donating group is present hence will have higher bond polarity of - C = O bond which in turn shows greater acidity than acetic acid.

Explain why acetaldehyde undergoes aldol condensation, but formaldehyde does not.

Aldol condensation: Aldehydes and ketones having at least one α - hydrogen undergo a reaction in the presence of dilute alkali as catalyst to form β - hydroxy aldehydes or β - hydroxy ketones, respectively. This is known as Aldol reaction. If we observe the structures of acetaldehyde and formaldehyde it is cleared that only acetaldehyde contains α - hydrogens but formaldehyde does not. Because of this reason formaldehyde does not undergo Aldol condensation.

Write chemical equations to illustrate the name reaction HVZ reaction.

Carboxylic acids having an α - hydrogen are halogenated at the α - position on treatment with chlorine or bromine in the presence of small amount of red phosphorus to give α - halocarboxylic acids. The reaction is known as Hell-Volhard-Zelinsky reaction. CH 3 - CH 2 - COOH → Br 2 / P CH 3 − CHBr − COOH → Br 2 / P CH 3 − CBr 2 − COOH → Br 2 / P No further reaction . In the above equation the reaction has been stopped in the last step due to the non-availability of α - hydrogen in the last step's substrate.

Write chemical equations to illustrate the name reaction rosenmund’s reduction.

Rosenmund's reduction is the reduction of acyl chlorides to form aldehydes. In this case, controlled reduction of acid chlorides is needed to be achieved. For this the catalyst used is Palladium and BaSO 4 , which is called as lindlar's catalyst. BaSO 4 provides smaller surface area for reactant and hence control the further reduction of aldehydes to primary alcohols.

Write chemical equations to illustrate the name reaction clemmensen’s reduction.

The Clemmensen's reduction is carried out in acidic media. This reduction is used to reduce aldehydes and ketones to hydrocarbons. Zinc amalgam and concentrated hydrochloric acid are used as Clemmensen's reagent. Clemmensen's reduction is a reaction which involves the reduction of a carbonyl compounds to form hydrocarbons and the mercury alloyed with the zinc does not participate in the reaction, it serves only to provide a clean active metal surface. The equation for this reaction as shown below,