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Correct option is (b) False

The explanation is: The COOH group is a deactivating group and does not UNDERGO Friedel-Crafts alkylation. The catalyst AlCl3 being a Lewis ACID, GETS bonded to the CARBOXYL group, and the methyl group does not get substituted in the RING.

The correct ANSWER is (a) True

Explanation: Acetic acid as well as ethanol consist of an OH GROUP and reaction with SOCl2 results in the cleavage of C-OH bond with the hydroxyl group to be replaced by Cl ATOM. The only difference is that acetic acid forms acetyl chloride, whereas ethanal forms ethyl chloride.

Correct OPTION is (c) CO2

Explanation: Unlike phenols, carboxylic acids react with WEAK BASES LIKE hydrogen carbonates to give carbon DIOXIDE, along with sodium carboxylate salt and water.

Correct option is (d) Presence of more alkyl groups in carboxylic acids

The explanation: The OH bond in carboxylic acids is more strongly polarised DUE to the presence of adjacent electron withdrawing CO group. This results in STRONGER hydrogen bonds. Also, the presence of alkyl groups should increase the POLARITY of OH bond as they are electron releasing in nature. Furthermore, carboxylic acids form two hydrogen bonds between molecules compared to the only one between alcohols.

Right answer is (C) Acrylic acid

Explanation: The IUPAC NAME of acrylic acid is prop-2-enoic acid, which indicates the PRESENCE of a double bond at the SECOND carbon, the one next to the CARBOXYL carbon. Its formula is (CH2=CHCOOH).

Right choice is (d) CO, HCL and CuCl

The best I can EXPLAIN: When benzene or its DERIVATIVE is TREATED with CO and HCl in the presence of anhydrous AlCl3 or CuCl, it gives a benzaldehyde or substituted benzaldehyde. This is known as Gatterman-Koch reaction.

The correct option is (a) True

Easy explanation: Side chain chlorination of toluene in the PRESENCE of light (represented by hv) gives benzal chloride which on HYDROLYSIS gives benzaldehyde. This is an important COMMERCIAL METHOD for the PRODUCTION of benzaldehyde.

Correct choice is (a) True

The best EXPLANATION: VANILLIN consists of a benzene ring substituted with CHO GROUP and OH group on opposite SIDE. Additionally, there is a methoxy group at meta position with respect to the aldehydic group. Its IUPAC name is 4-Hydroxy-3-methoxybenzaldehyde.

The correct CHOICE is (C) Food preservative

Easiest EXPLANATION: Methanoic acid is the simplest acid and is used in rubber manufacturing, leather tanning, textile dyeing and finishing and ELECTROPLATING industries.

The correct answer is (b) 2

Easy explanation: Two MOLECULES combine with the loss of one water molecule (H ATOM from one molecule and OH GROUP from another molecule) when heated with dehydrating AGENTS like H2SO4 to give acetic anhydride.

The correct option is (d) Benzaldehyde

The explanation is: ALDEHYDES and ketones that have at least one α-hydrogen ATOM undergo aldol CONDENSATION, where the α-hydrogen of one molecule becomes attached to the CARBONYL carbon of the second molecule to form aldols and ketols RESPECTIVELY.

Right option is (a) True

The EXPLANATION: CF3 group is highly electronegative due to the presence of three F atoms and has a GREATER ELECTRON withdrawing and stabilizing INFLUENCE on carboxylate ion than NO2 group.

Right choice is (b) 2-Chlorobutanoic acid

To explain I would say: Halogen substituted carboxylic ACIDS are stronger acid than their respective parent acids, because of the ELECTRON withdrawing and stabilizing nature of the halogen. Furthermore, as the DISTANCE of the halogen form the COOH GROUP increases, the electron withdrawing INFLUENCE decreases, and therefore the acidic character decreases.

Correct option is (b) butanoic acid

Explanation: Ethyl butanoate (CH3CH2CH2COOC2H5) on BASIC HYDROLYSIS forms CH3CH2CH2COONa and ethanol. Then this sodium carboxylate COMPOUND GETS ACIDIFIED to give butanoic acid.

Correct choice is (a) Methanal > ETHANAL > Acetone

Best explanation: Methanal is the most reactive among aldehydes and ketones due to electronic and STEARIC reasons. Methanal (HCHO) does not have any alkyl groups that RELEASE ELECTRONS toward carbonyl carbon, thus MAKING it more electrophilic. Also, presence of only two H atoms do not provide any hinderance to the attack of incoming nucleophile.

The correct answer is (b) CrO2Cl2

Explanation: This is known as Etard reaction. The CHROMYL chloride oxidises the METHYL group to a CHROMIUM complex in CS2. This complex on HYDROLYSIS gives benzaldehyde.

The correct OPTION is (d) Cyclohexanecarbaldehyde

Best explanation: When the CHO group is ATTACHED to a ring, the suffix carbaldehyde is ADDED after the NAME of the CYCLOALKANE. The numbering of the ring carbons starts form the carbon attached to the aldehyde group.

The correct option is (a) True

Easiest EXPLANATION: This is because BENZENE ring has a planar STRUCTURE and can pack more closely in the crystal lattice than aliphatic acids, which have a zig-zag structure. The melting of aromatic acids are also usually higher due to the same REASON.

Right OPTION is (d) Acetone

The BEST I can EXPLAIN: Aldehydes and ketones are reduced to respective hydrocarbons when treated with hydrazine followed by heating with KOH/NaOH in high boiling solvents. This is known as Wolff-Kishner reduction. The CO GROUP of acetone is reduced to CH2, and propane is OBTAINED.

Correct answer is (a) 1:1

Best explanation: Two SOLUTIONS, aqueous copper SULPHATE and alkaline sodium potassium tartarate are COMBINED in equal proportions to result in Fehling’s solution. This is an important reagent in the conduction of Fehling’s TEST.

Right choice is (d) Carballylic acid

To elaborate: Malonic acid, glutaric acid and ADIPIC acid are dicarboxylic acids with 3, 5 and 6 carbon atoms in their structures RESPECTIVELY. Carballylic acid, ALSO known as tricarballylic acid is a tricarboxylic acid having 3 carbon atoms EXCLUDING the three carboxyl carbons in its structure. Its IUPAC NAME is Propane-1,2,3-tricarboxylic acid.

Correct CHOICE is (C) Ethyl benzene

Best EXPLANATION: The carbonyl group of acetophenone is REDUCED to CH2 group and results in the formation of a HYDROCARBON when subjected to Clemmensen reduction, i.e., reaction with Zn-Hg and concentrated HCl.

The correct answer is (b) 2,4-Dimethylpentan-3-one

Explanation: The formula of diisopropyl ketone is (CH3)2CHCOCH(CH3)2 which consists of 7 carbon atoms. The longest parent chain including the keto group is of 5 carbon atoms, leaving out one C ATOM from the methyl group at each end. This is a symmetric ketone and the methyl groups are present at the SECOND and fourth carbon starting from any one end and the C-O double BOND is present at the third carbon.

Right option is (d) C6H5COOCOC6H5

Easiest EXPLANATION: Benzoic acid on heating with a strong dehydrating agent like P2O5 FORMS its corresponding anhydride, i.e., benzoic anhydride, which CONSISTS of TWO C6H5C=O groups bridged by a (-O-) GROUP.

Right answer is (B) C2H5COOH > CH3COOH > HCOOH

To EXPLAIN: The boiling points INCREASE with the increase in molecular mass, because as the size of alkyl group increases, the magnitude of van der WAAL forces increases, thus making the bonds difficult to BREAK.

Correct choice is (d) NaBH4

Best EXPLANATION: CARBOXYLIC acids on reduction with LiAlH4, B2H6 or H2 in the PRESENCE of suitable MEDIUM, are reduced to alcohols. The COOH group is reduced to CH2OH group. SODIUM borohydride cannot reduce the carboxyl group.

Right choice is (a) Cold water

For EXPLANATION I would say: The large hydrophobic benzene ring of benzoic acid prevents the carboxyl group from taking PART in hydrogen bonding. However, benzoic acid is soluble in non-polar solvents like benzene, ether, ALCOHOL, CHLOROFORM, ETC.

The correct option is (a) acetate ion

For EXPLANATION: Acid CHLORIDES are readily hydrolysed with aqueous base to GIVE carboxylate ions which further give CORRESPONDING carboxylic acids on acidification. It can be directly obtained by direct hydrolysis with WATER.

Correct option is (d) Pentan-3-one

Easiest explanation: Pentan-2-one consists of a CH3CO groups and gives POSITIVE for IODOFORM test. Propan-2-ol and butan-2-ol pass iodoform test because of the PRESENCE of CH3CH(OH) group which gets oxidised to CH3O group during reaction. On the other hand, pentan-3-one consists of only ethyl groups on either side of the carbonyl carbon and is not oxidised by SODIUM hypoiodite to give iodoform.

Correct option is (d) Benzaldehyde > Acetophenone > Benzophenone

The BEST I can explain: Generally, the AROMATIC carbonyl compounds are less reactive than corresponding aliphatic compounds. From benzaldehyde to acetophenone to benzophenone, the number of ELECTRON releasing groups increases and the magnitude of POSITIVE charge on carbonyl carbon REDUCES, hence decreasing its reactivity towards nucleophile attack.

Correct OPTION is (b) False

The explanation is: Propanone has two CH3 groups, one on either side of the CO group, whereas PROPANAL has only one CH3CH2 group. This makes propanone more polar because of the HIGHER electron releasing EFFECT of two alkyl groups. The boiling POINT of propanal is 322K and that of propanone is 329K.

Right option is (d) Friedel-Craft acylation reaction

To explain I would say: Friedel-Crafts acylation of BENZENE produces an aromatic KETONE and not BENZALDEHYDE. Benzene on Gatterman-Koch reaction GIVES benzaldehyde, so does toluene on Etard reaction. Rosenmund reaction also gives benzaldehyde but from benzoyl CHLORIDE.

Right answer is (B) Zinc DUST

To EXPLAIN: Addition of water to propyne in the presence of H2SO4 and HgSO4 gives acetone. Zinc dust is an important reagent in the OZONOLYSIS of alkenes.

Correct option is (B) DIBAL-H

Explanation: DIBAL-H or diisobutylaluminium HYDRIDE is a reducing agent which are used to REDUCE nitriles to imines or ESTERS to aldehydes. These are important in the preparation of aldehydes.

Correct option is (b) Br2-FEBR3

To elaborate: Benzoic ACID undergoes electrophilic SUBSTITUTION with bromine at the META POSITION in the presence of FeBr3 to form 3-bromobenzoic acid and hydrogen bromide as side product.

Right option is (c) CH3COOK

The explanation: Aqueous solutions of sodium or POTASSIUM salts of carboxylic ACIDS on electrolysis, undergo decarboxylation and FORM hydrocarbons having twice the number of carbon atoms as present in the alkyl GROUP of the acid. Since ethane has two C atoms, the alkyl group of the acid should be CH3.

Correct choice is (B) False

To explain I WOULD say: Both compounds contain a sp^2 hybridised carbon atom next to the COOH group, but the double BOND of a benzene ring is less electron releasing in nature than the vinyl carbon double bond of acrylic acid. This is because DELOCALISATION in the resonance structures of benzoic acid destroys its aromatic character. Hence, benzoic acid is stronger than acrylic acid.

Correct ANSWER is (b) -logKa

To explain: KEQ is the equilibrium constant of a REACTION and Ka is the ACID dissociation constant which is Keq[H2O]. The strength of an acid is generally by its pKa value rather than its Ka value.

The correct answer is (c) Propiolic acid > Acrylic acid > ACETIC acid

To explain: The electronegativity of CARBON increases from sp^3 to sp^2 to sp hybridisation. The carbon attached to the CARBONYL carbon of propionic acid id sp hybridised (due to triple bond) ang has a HIGHER inductive effect on the COOH group and as a result has higher ACIDITY compared to acrylic acid (sp^2 carbon) or acetic acid (sp^3 carbon).

Correct OPTION is (d) dimers

For EXPLANATION: The intermolecular hydrogen BONDS between carboxylic ACIDS are not broken even in VAPOUR phase. In fact, most carboxylic acids exist as dimer in vapour phase or in aprotic solvents.

The correct option is (d) o-Xylene and n-Butyl benzene

For explanation: All mono-substituted ALKYL benzenes, with primary or secondary alkyl groups, on VIGOROUS oxidation give benzoic acid. The entire side chain is oxidised irrespective of the length. In case of o-xylene, there are two methyl groups on the benzene RING and both of them are oxidised to carboxyl group, resulting in PHTHALIC acid.