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Right choice is (a) OH

Best explanation: Given that the COMPOUND has a higher PKA value than benzoic acid, it should have weaker acidic STRENGTH than benzoic acid. This means, that X should be an electron donating group that destabilises the compound and REDUCES its acidic strength. Since is an electron RELEASING group, the X group should be OH.

Right answer is (d) Iodoacetic acid<BR>
For explanation: HIGHER the electronegativity of a halogen, greater will be its electron withdrawing EFFECT, and stronger will be the acid. SINCE electronegativity of halogens decrease in the order F > Cl > Br > I, iodoacetic acid will be the weakest and hence will have the highest pKa value.

Correct option is (c) A < B

The BEST explanation: Compound A has a METHOXY group (electron donating) and compound B has nitro group (electron withdrawing). In simple terms, the electron withdrawing groups stabilise the carboxylate ION and STRENGTHEN the acid, whereas electron DONATION groups weaken the acid.

The correct OPTION is (d) benzyl alcohol

The EXPLANATION is: Only primary ALCOHOLS undergo oxidation in the presence of common oxidising agents followed by reaction with H3O^+ to give the respective carboxylic acids. This reaction is proceeded by the removal of both hydrogen atoms from the alpha CARBON and formation of a DOUBLE bond between C and O.

The correct ANSWER is (a) -7

For explanation: Generally, carboxylic acids are weaker acids than mineral acids like hydrochloric acid. ALSO, mineral acids are strong with pKa values USUALLY LESS than 1. Hence, the pKa value of carboxylic acids will be higher.

Right choice is (B) CrO3 in H2SO4

The explanation is: Chromium TRIOXIDE in an aqueous solution with sulphuric acid in KNOWN as Jones reagent. It Is an important compound in the preparation of carboxylic ACIDS from alcohols.

Correct CHOICE is (b) False

The explanation is: The carboxyl group is capable of forming THREE resonance STRUCTURES in comparison to the two formed by carbonyl group. This makes the carboxyl carbon less electrophilic than the carbonyl carbon.

Correct option is (c) rancid BUTTER

The best I can EXPLAIN: The common names of some CARBOXYLIC acids gives an idea of where it was first obtained from in nature. Butyric acid comes from the LATIN word butyrum meaning butter.

Right option is (b) 2

To explain I would say: Phthaldehyde is an AROMATIC compound containing two CHO groups, one on each adjacent CARBON of the BENZENE ring. To give equal importance to both the aldehydic groups, it is NAMED as benzene-1,2-dicarbaldehyde in the IUPAC system.

Right CHOICE is (a) Formaldehyde

The EXPLANATION: Methanal exists as foul-smelling gas at room temperature. Ethanal is a volatile liquid which boils at 294K. Other ALDEHYDES and ketones exist as either LIQUIDS or solids at room temperature.

The correct answer is (a) -CHO

Explanation: If a COMPOUND contains both aldehyde and ketone groups, then the FORMER is CONSIDERED as the principal functional group, and the ketone is regarded as SUBSTITUENT. Thus, it is named as a derivative of alkanal.

The correct answer is (b) m-Nitrobenzoic acid

Explanation: Benzoic acid UNDERGOES RING SUBSTITUTION in which the COOH group acts as a deactivating group and is meta-directing in nature.

Correct option is (B) False

For explanation: tert-Butyl benzene consists of a tertiary group with no benzylic H. It is highly stable and does not UNDERGO OXIDATION even under drastic conditions, to GIVE aromatic CARBOXYLIC acids.

Correct option is (b) o-Toluic acid

Easiest explanation: Although CH3 is an electron releasing group and should reduce the acidic character of acids by destabilizing it, the PRESENCE of CH3 group at ortho POSITION has a reverse effect and increases the acidic strength compared to benzoic acid. This is due to a combination of STEARIC and electronic FACTORS.

The correct CHOICE is (b) False

For explanation: Semicarbazone is the name of the product formed from the rapid DEHYDRATION of the product of the reaction between SEMICARBAZIDE and aldehyde or ketone in ACIDIC medium. Semicarbazide is the reagent and Semicarbazone is the N-substituted carbonyl derivative.

The correct choice is (a) Succinic ACID

The explanation is: Succinic acid is a dicarboxylic acid with 4 carbon atoms in its structure. Its IUPAC name is butanedioic acid. Crotonic acid is but-2-enoic acid, whereas cinnamic acid and mandelic acid consists only a SINGLE CARBOXYL group along with a PHENYL group.

The correct OPTION is (d) acetone

Explanation: Reduction of acetone in the PRESENCE of catalysts like Ni, Pt or Pd converts it into propan-2-ol, which is a secondary alcohol. It can ALSO be reduced by the reaction with LiAlH4 or NABH4. ALDEHYDES on similar reaction give primary alcohols.

Correct choice is (d) Benzaldehyde

The best I can explain: Rosenmund reaction is exclusively used for the PREPARATION of aldehydes by the substitution of chloride by hydrogen. Given this, methanal cannot be formed from this reaction because its corresponding ACYL chloride, i.e., FORMYL chloride, is unstable at room temperature. Benzaldehyde is formed from BENZOYL chloride.

Correct option is (C) Alkyl phenyl

To elaborate: For EXAMPLE, the ketone with COCH3 group attached to a benzene RING is named as acetophenone. Also, DIPHENYL ketone as benzophenone.

The correct option is (a) Sodium benzoate

Easy explanation: When C6H5COOH reacts with NaOH, a SALT CALLED sodium benzoate is FORMED. When an aqueous salt SOLUTION is prepared from this product, it acts as a PRESERVATIVE. It is identified by the code E211.

Right choice is (d) nucleophilic substitution

For explanation: When carboxylic acids are heated with alcohols with suitable catalyst, esters are FORMED. This is a REVERSIBLE reaction due to all the INDIVIDUAL STEPS involved in the mechanism of this reaction are reversible in nature. It is a type of nucleophilic ACYL substitution reaction.

The correct answer is (a) H3PO3

Easy EXPLANATION: Three molecules of ETHANOIC acid react with one molecule of PCL3 to give three molecules of ethanoyl CHLORIDE and one molecule of PHOSPHOROUS acid (H3PO3).

Right choice is (a) Benzoic acid > m-Nitrobenzoic acid > p-Nitrobenzoic acid

Easy EXPLANATION: Nitro group is electron withdrawing in NATURE and increases the acidic strength of acids. The electron withdrawing effect of NO2 is PRONOUNCED at para POSITION more than meta position, hence the p-isomer is more acidic and has a lower pKa value than m-isomer.

Right CHOICE is (b) False

To elaborate: Salicylic acid consists of a hydroxy group on the BENZENE ring at ortho, meta or para POSITION with respect to the carboxyl group. It is NAMED as hydroxybenzoic acid in IUPAC system.

Right OPTION is (C) 3,3-Dimethylbutanoic acid

Best explanation: The LONGEST parent carbon CHAIN consists of 4 carbon atoms including the carboxyl carbon and one methyl group attached to the tertiary carbon. The other two methyl groups act as substituents on the carbon, which is now the third carbon.

Correct CHOICE is (a) O3/H2O-Zn dust

Explanation: But-2-ene on ozonolysis FOLLOWED by reaction with WATER and ZINC dust gives ethanal or sometimes a mixture of an aldehyde and ketone depending on the substitution pattern.

Correct choice is (d) γ-Methylcyclohexanecarbaldehyde

Best explanation: This compound is a cyclic aldehyde where numbering starts from the carbon to which the CHO GROUP is ATTACHED. So, the carbon to which METHYL group is attached is the third carbon. In the COMMON system, this carbon is known as the gamma carbon.

The CORRECT OPTION is (b) 1

To explain: Formaldehyde is the common NAME of the SIMPLEST aldehyde, methanal. Its formula is HCHO and only one carbon which is also a part of the carbonyl GROUP.

Correct answer is (a) Caproic acid

Explanation: The FIRST three members of carboxylic acids have pungent SMELL. The next six members have a faint unpleasant odour. The higher members (lauric acid, myristic acid, palmitic acid) are PRACTICALLY odourless DUE to their low VOLATILITY.

Right option is (a) HCOOH

Easiest explanation: The rate at which carboxylic ACIDS are esterified DEPENDS upon the stearic HINDERANCE and to some EXTENT the acidic strength of the acid, as it is a nucleophilic substitution reaction. Since formic acid has the lowest molecular mass and SMALLEST group, it is the most reactive.

Right option is (c) one NH3

The best explanation: Phthalic ACID on reaction with NH3 forms ammonium phthalate, which on heating loses TWO H2O molecules, one from each COONH4 GROUP, to form phthalamide. This on further strong heating loses one NH3 MOLECULE to form PHTHALIMIDE, which is an imide derivative of phthalic anhydride.

Right answer is (d) CYCLIC ketals

For explanation I would say: Dihydric alcohols LIKE ETHYLENE glycol REACT with aldehydes and ketones to directly form cyclic products known as cyclic acetals and cyclic ketals respectively. The cyclic ketals are also known as ethylene glycol ketals.

The CORRECT answer is (d) Butanal

The explanation: As the SIZE of the ALDEHYDE molecule increases, the odour becomes less pungent and more FRAGRANT. Methanal is the most pungent smelling aldehyde.

Correct ANSWER is (C) SNCL2

Explanation: Nitriles are CONVERTED to respective imines with SnCl2 in the presence of HCl, which on hydrolysis gives corresponding aldehyde.

The correct choice is (b) HCl gas

To elaborate: HCl gas and concentrated H2SO4 are catalyst which provide a proton for the protonic ATTACK on the carbonyl oxygen of ACETIC acid, which further activates the carbonyl groups TOWARDS nucleophilic addition of ethanol, which ultimately results in the formation of ETHYL acetate, which is an ester.

Correct CHOICE is (c) p-Nitrobenzaldehyde

To elaborate: Addition of hydrogen cyanide is a nucleophilic reaction. CH3 and COCH3 are electron releasing groups which decrease the positive charge on CARBONYL carbon, whereas NO2 is an electron withdrawing group which INCREASES the electrophilicity of carbonyl carbon, MAKING it more reactive toward hydrogen cyanide than benzaldehyde.

Correct answer is (c) 322 K

To EXPLAIN I would say: The boiling point of aldehydes are higher than those of non-polar hydrocarbons of comparable molecular masses. HOWEVER, their boiling points are LOWER than comparable alcohols, due to the absence of intermolecular HYDROGEN bonding.

The correct option is (a) AMMONIACAL silver NITRATE solution

Easy explanation: Tollen’s reagent is prepared by adding ammonium hydroxide solution to silver nitrate solution till the grey precipitate of Ag2O FIRST FORMED just gets dissolved.

Right choice is (b) Propanoic acid and ethanoic acid

The best explanation: Ketones undergo oxidation accompanied by C-C bond cleavage to give a mixture of carboxylic acids having lesser NUMBER of carbon atoms than the parent ketone. In case of petan-2-one (which is unsymmetrical), the cleavage OCCURS such that the CO group stays with the SMALLER alkyl group (Popoff’s rule). Hence, the bond between C-2 and C-3 will be broken to give a mixture of ethanoic acid and propanoic acid.

The CORRECT CHOICE is (c) PD over BaSO4

Best explanation: Acyl chlorides are hydrogenated in the presence of catalyst PALLADIUM over barium sulphate. This is known as Rosenmund reaction.

The correct option is (a) Capric ACID

The explanation is: Soaps are sodium or potassium salts of long chain fatty ACIDS like stearic, oleic, palmitic acids, etc. Capric acid is decanoic acid and CONTAINS 10 carbon atoms and is not classified as a fatty acid.