Chapter 26

The structure of compounds \(J, K\) and \(L\) respecitvely, are - (a) \(\mathrm{PhCOCH}_{3}, \mathrm{PhCH}_{2} \mathrm{COCH}_{3}\) and \(\mathrm{PhCH}_{2} \mathrm{COO}^{-} \mathrm{K}^{+}\) (b) \(\mathrm{PhCHO}, \mathrm{PhCH}_{2} \mathrm{CHO}\) and \(\mathrm{PhCOO}^{-} \mathrm{K}^{+}\) (c) \(\mathrm{PhCOCH}_{3}, \mathrm{PhCH}_{2} \mathrm{CHO}\) and \(\mathrm{CH}_{3} \mathrm{COO}^{-} \mathrm{K}^{+}\) (d) \(\mathrm{PhCHO}, \mathrm{PhCOCH}_{3}\) and \(\mathrm{PhCOO}^{-} \mathrm{K}^{+}\)

Statement-1: \(p\)-Hydroxybenzoic acid has a lower boiling point than \(o\)-hydroxybenzoic acid. Statement-2 : o-Hydroxybenzoic acid has intramolecular hydrogen bonding.

An organic compound 'A' on treatment with ethyl alcohol gives a carboxylic acid ' \(\mathrm{B}\) ' and compound ' \(\mathrm{C}\) '. Hydrolysis of ' \(\mathrm{C}\) ' under acidic conditions gives 'B' and 'D'. Oxidation of ' \(\mathrm{D}\) ' with \(\mathrm{KMnO}_{4}\) also gives ' \(\mathrm{B}^{\prime}\). ' \(\mathrm{B}\) ' on heating with \(\mathrm{Ca}(\mathrm{OH})_{2}\) gives ' \(\mathrm{E}\) ' (molecular formula, \(\left.\mathrm{C}_{3} \mathrm{H}_{6} \mathrm{O}\right) .^{\text {' } \mathrm{E}}\) ' does not give Tollen's test and does not reduce Fehling's solution but forms a 2,4 dinitrophenylhydrazone. Identify ' \(\mathrm{A}^{\prime},{ }^{\text {' }} \mathrm{B}^{\prime}\), ' \(\mathrm{C}^{\prime}\), ' \(\mathrm{D}\) ' and ' \(\mathrm{E}\) '.

Statement-1 : Dimethyl sulphide is commonly used for the reduction of an ozonide of an alkene to get the carbonyl compounds. Statement-2 : It reduces the ozonide giving water soluble dimethyl sulphoxide and excess of it evaporates.

Compound ' \(\mathrm{X}\), containing chlorine on treatment with strong ammonia gives a solid ' \(Y\) ' which is free from chlorine. 'Y' analysed as \(\mathrm{C}=49.31 \%, \mathrm{H}=\) \(9.59 \%\) and \(\mathrm{N}=19.18 \%\) and reacts with \(\mathrm{Br}_{2}\) and caustic soda to give a basic compound ' \(\mathrm{Z}^{\prime} .{ }^{'} \mathrm{Z}\) ' reacts with \(\mathrm{HNO}_{2}\) to give ethanol. Suggest structures for ' \(\mathrm{X}\) ', ' \(\mathrm{Y}^{\prime}\) and \(^{6} \mathrm{Z}^{\prime}\).

$$ A\left(\mathrm{C}_{6} \mathrm{H}_{12}\right) \stackrel{\mathrm{HCl}}{\longrightarrow} \underset{\left(\mathrm{C}_{6} \mathrm{H}_{13} \mathrm{Cl}\right)}{B+C} $$ \(B \stackrel{\text { alc. KOH }}{\longrightarrow} D(\) isomer of \(A)\) \(D\) ozonolysis \({\longrightarrow} E^{\text {(it gives negative test with Fehling solution but }}\) responds to iodoform test). \(A\) Ozonolysis \(F+G\) (both gives positive Tollen's test but do not give iodoform test).

(i) \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{COOH} \quad \stackrel{\mathrm{PCl}_{5}}{\longrightarrow} C \stackrel{\mathrm{NH}_{3}}{\longrightarrow}\) $$ D \stackrel{\mathrm{P}_{2} \mathrm{O}_{5}}{\longrightarrow} \mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CN} \quad \stackrel{\mathrm{H}_{2}^{/ \mathrm{Ni}}}{\longrightarrow} E $$ Identify \(C, D\) and \(E\). [1991 - 2 Marks] (ii) \(\mathrm{H}_{3} \mathrm{C}-\mathrm{CH}=\mathrm{CH}-\mathrm{CHO} \stackrel{\mathrm{NaBH}_{4}}{\longrightarrow} F\) $$ \frac{\mathrm{HCl}}{\mathrm{ZnCl}_{2}} G \underset{\mathrm{H}^{+}}{\stackrel{\mathrm{KCN}}{\longrightarrow}} \mathrm{H} $$ Identify \(F, G\) and \(H\).

Compound ' \(A\) ' of molecular formula \(\mathrm{C}_{9} \mathrm{H}_{7} \mathrm{O}_{2} \mathrm{Cl}\) exists in keto form and predominantly in enolic form ' \(B\) '. On oxidation with \(\mathrm{KMnO}_{4}\), 'A' gives \(m\)-chlorobenzoic acid. Identify ' \(A\) ' and ' \(B\) '.

Compound \(A\left(\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{2}\right)\) on reduction with \(\operatorname{LiAlH}_{4}\) yielded two compounds \(B\) and \(C\). The compound \(B\) on oxidation gave \(D\), which on treatment with aqueous alkali and subsequent heating furnished \(E\). The latter on catalytic hydrogenation gave \(C\). The compound \(D\) was oxidized further to give \(F\) which was found to be a monobasic acid (molecular weight \(=60.0\) ). Deduce the structures of \(A, B, C, D\) and \(E\).

The sodium salt of a carboxylic acid, \(A\), was produced by passing a gas, \(B\), into an aqueous solution of caustic alkali at an elevated temperature and pressure. \(A\), on heating in presence of sodium hydroxide followed by treatment with sulphuric acid gave a dibasic acid, \(C\). A sample of \(0.4 \mathrm{~g}\) of acid \(C\), on combustion gave \(0.08 \mathrm{~g}\) of water and \(0.39 \mathrm{~g}\) of carbon dioxide. The silver salt of the acid \(C\) weighing \(1.0 \mathrm{~g}\) on ignition yielded \(0.71 \mathrm{~g}\) of silver as residue. Identify \(A, B\) and \(C\).

An organic compound A, \(\mathrm{C}_{6} \mathrm{H}_{10} \mathrm{O}\) on reaction with \(\mathrm{CH}_{3} \mathrm{MgBr}\) followed by acid treatment gives compound \(\mathbf{B}\). The compound \(\mathbf{B}\) on ozonolysis gives compound \(\mathbf{C}\), which in presence of a base gives 1- acetylcyclopentene D. The compound \(\mathbf{B}\) on reaction with HBr gives compound \(\mathbf{E}\). Write the structures of \(\mathbf{A}, \mathbf{B}, \mathbf{C}\) and \(\mathbf{E}\). Show how \(\mathbf{D}\) is formed from \(\mathbf{C}\) ?

An organic compound (A) on treatment with acetic acid in the presence of sulphuric acid produces an ester (B), (A) on mild oxidation gives (C), (C) with \(50 \%\) potassium hydroxide followed by acidification with dilute hydrochloric acid generates (A) and (D), (D) with phosphorus pentachloride followed by reaction with ammonia gives (E), (E) on dehydration produces hydrocyanic acid. Identify the compounds \(\mathrm{A}, \mathrm{B}, \mathrm{C}, \mathrm{D}\) and \(\mathrm{E}\).

An aldehyde \(A\left(\mathrm{C}_{11} \mathrm{H}_{8} \mathrm{O}\right)\), which does not undergo self aldol condensation, gives benzaldehyde and two moles of \(B\) on ozonolysis. Compound \(B\), on oxidation with silver ion gives oxalic acid. Identify the compounds \(A\) and \(B\).

A liquid (X), having a molecular formula \(\mathrm{C}_{6} \mathrm{H}_{12} \mathrm{O}_{2}\) is hydrolysed with water in the presence of an acid to give a carboxylic acid \((\mathrm{Y})\) and an alcohol \((\mathrm{Z})\). Oxidation of \((\mathrm{Z})\) with chromic acid gives \((\mathrm{Y}) .\) What are the structures of \((\mathrm{X})\), (Y) and \((\mathrm{Z}) ?\)

Arrange the following in increasing ease of hydrolysis \(\mathrm{CH}_{3} \mathrm{COOC}_{2} \mathrm{H}_{5}, \mathrm{CH}_{3} \mathrm{COCl},\left(\mathrm{CH}_{3} \mathrm{CO}\right)_{2} \mathrm{O}, \mathrm{CH}_{3} \mathrm{CONH}_{2} .\)

An organic compound \(A, \mathrm{C}_{8} \mathrm{H}_{6}\), on treatment with dilute sulphuric acid containing mercuric sulphate gives a compound \(B\), which can also be obtained from a reaction of benzene with an acid chloride in the presence of anhydrous aluminium chloride. The compound \(B\), when treated with iodine in aqueous \(\mathrm{KOH}\), yields \(C\) and a yellow compound \(D\). Identify \(A, B, C\) and \(D\) with justification. Show how \(B\) is formed from \(A\).

Write down the reactions involved in the preparation of the following using the reagents indicated against it in parenthesis: Propionic anhydride from propionaldehyde \(\left[\mathrm{AgNO}_{3} / \mathrm{NH}_{4} \mathrm{OH}, \mathrm{P}_{2} \mathrm{O}_{5}\right]\).

An alkene \((A)\) on ozonolysis yields acetone and an aldehyde. The aldehyde is easily oxidized to an acid \((B)\). When \(B\) is treated with bromine in presence of phosphorus, it yields a compound (C) which on hydrolysis gives a hydroxy acid \((D)\). This acid can also be obtained from acetone by reaction with hydrogen cyanide followed by hydrolysis. Identify the compounds \(A, B, C\) and \(D .\)

An unknown compound of carbon, hydrogen and oxygen contains \(69.77 \%\) carbon and \(11.63 \%\) hydrogen and has a molecular weight of 86\. It does not reduce Fehling solution, but forms a bisulphite addition compound and gives a positive iodoform test. What are the possible structures for the unknown compound?

Arrange the following in : Increasing reactivity towards HCN \(\mathrm{CH}_{3} \mathrm{CHO}, \quad \mathrm{CH}_{3} \mathrm{COCH}_{3}, \quad \mathrm{HCHO}, \quad \mathrm{C}_{2} \mathrm{H}_{5} \mathrm{COCH}_{3}\)