Chemistry: CUET Mock Test - 4 - CUET MCQ

The -NHCOCH₃ group forms two resonance structures, where the lone pair of nitrogen interacts with the lone pairs on oxygen atom. This makes the lone electron pair on N less available for donation to benzene ring.

Both ethylamine and diethylamine on reaction with CH₃CH₂Br eventually gives quaternary ammonium salt. Hence, the alkylation of primary amines cannot be used as a distinction method.

Secondary amines on reaction with Hinsberg’s reagent produce sulphonamides without any hydrogen atom attached to the nitrogen atom. Hence, it is not acidic and therefore insoluble in alkali. The amide produced in this case is N-ethyl-N-methylbenzenesulphonamide.

Secondary amines react slowly with nitrous acid at low temperatures to give yellow oily nitrosoamines. Diethylamine specifically produces N,N-diethylnitrosoamine.

Magnetic strength depends on the number of unpaired electrons possessed by the element. Iron, Cobalt, Nickel and Copper have 4, 3, 2 and 1unpaired electron respectively. Hence, the correct order of magnetic strength is: Fe > Co > Ni > Cu.

Nitrogen gas is evolved due to the decomposition of diazonium salts which are formed from the reaction of 1° aliphatic amines with HNO₂. This is used in the estimation of amino acids and proteins.

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.

Ethyl bromide on reaction with alc. KCN gives ethyl cyanide by nucleophilic substitution. Nitriles can be hydrolysed to give amides and on further heating give a carboxylic acid which contains one more carbon than the original ethyl bromide. Hence, the acid contains three C atoms, making it propanoic acid.

Only Diamagnetic substances show a negative value of magnetic susceptibility. In the given list: oxygen and aluminium are paramagnetic, iron is ferromagnetic and nitrogen is diamagnetic. Therefore, Nitrogen has a negative value of magnetic susceptibility.

p-Xylene is a dimethyl substituted benzene which on vigorous oxidation, gets oxidised to an aromatic dicarboxylic acid, with the two carboxyl groups at para positions with respect to each other. This compound is called terephthalic acid.

Methyl magnesium bromide (Grignard reagent) on reaction with CO₂ forms an addition product containing an additional C carbon atom. This is decomposed in the presence of mineral acid to form propanoic acid.

Benzoic ethanoic anhydride (C₆H₅COOCOCH₃) is easily hydrolysed with water to give its corresponding acids, benzoic acid (by adding H to C₆H₅COO) and ethanoic acid (by adding OH to COCH₃).

Ethyl butanoate (CH₃CH₂CH₂COOC₂H₅) on basic hydrolysis forms CH₃CH₂CH₂COONa and ethanol. Then this sodium carboxylate compound gets acidified to give butanoic acid.

The Néel temperature or magnetic ordering temperature is the temperature above which an antiferromagnetic material becomes paramagnetic. The Critical temperature of a gas is the temperature above which it cannot be liquefied by pressure alone. The temperature above which a ferromagnetic substance shows no ferromagnetism is called Curie temperature.

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.

Aldehydes are easily oxidized to carboxylic acids having the same number of carbon atoms as the parent aldehyde, when reacted even with mild oxidising agents like Tollen’s reagent.

Amides undergo hydrolysis in the presence of heat to give corresponding carboxylic acids along with ammonia gas. In the reaction shown, benzamide undergoes oxidation to form benzoic acid.

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.

The ethyl group, acetyl group and ethene group are all oxidised to potassium carboxylate groups which are further oxidised to carboxyl groups. In the case of 4-Methylacetophenone, there are two groups that will be oxidised to carboxyl groups, hence forming terephthalic acid instead of benzoic acid.

The MgBr group of 3-Chlorophenyl magnesium bromide (Grignard reagent) will be substituted by COOH group in the above reaction, to give a halogen substituted aromatic carboxylic acid.

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.

Benzoic acid reacts with ammonia in a reversible reaction to form ammonium benzoate by addition reaction. This salt then loses water on heating to form benzamide.

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.

Sodium acetate undergoes decarboxylation (loss of CO₂) when heated with soda lime. This is proceeded by the loss of COONa from the sodium salt and NaO from sodium hydroxide. They combine to form CH₄ and Na₂CO₃. The hydrocarbon formed has one less carbon atom than the parent acid.

Propanoic acid undergoes bromination at alpha-carbon in the presence of red phosphorus to give α-Bromopropanoic acid. This is known as Hell-Volhard-Zelinsky reaction.

Benzoic acid undergoes ring substitution in which the COOH group acts as a deactivating group and is meta-directing in nature.

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.

mmonium acetate (CH₃COO-NH₄⁺) is an ammonium salt which on heating at high temperatures, loses a water molecule to give acetamide (CH₃CONH₂).

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.

Soda lime is the 3:1 mixture of sodium hydroxide and calcium oxide, and is used in the decarboxylation reaction (loss of carbon dioxide) of carboxylic acids.