Aldehydes Ketones and Carboxylic Acids

Class 12th Chemistry – 12 Aldehydes, Ketones and Carboxylic acids MCQs

The reaction of Grignard reagent with methanal produces a ____ alcohol.

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The reaction of Grignard reagent with methanal produces a primary alcohol. These are reactions of the carbon-oxygen double bond, and so aldehydes and ketones react in exactly the same way - all that changes are the groups that happen to be attached to the carbon-oxygen double bond.

The higher carboxylic acids are ____ like solids and are practically odourless due to their low ____.

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The higher caboxylic acids are wax like solids and are practically odourless due to their low volatility.

What is the geometry of the carbonyl group?

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The carbon in the carbonyl group is sp2 hybridised and has a trigonal planar geometry.

Which of these aldehydes is a gas at room temperature?

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Only formaldehyde, the first member of the aliphatic aldehydes is a gas at room temperature. The rest of the members of both aliphatic as well as aromatic are liquids or solids at room temperature.

HCHO is known as ____.

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HCHO is known as formaldehyde or methanal.

Carbonyl compounds are of utmost importance to organic chemistry. They are important constituents of ____.

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Carbonyl compounds are of utmost importance to organic chemistry. Other than blood, they are constituents of all the options given.

What is the hybridisation of C in the carbonyl group?

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The carbon in the carbonyl group is sp2 hybridised and has a trigonal planar geometry.

The solubility of carboxylic acids ____ with ____ number of carbon atoms.

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The solubility of carboxylic acids decreases with increasing number of carbon atoms.

In aldehydes and ketones, carbon of the carbonyl group is

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Aldehydes and ketones have C = O in which C is Sp2 hybridized.

Formalin is an aqueous solution of

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Formalin is an aqueous solution of (40%) of formaldehyde.

Which of the following statements is not true for the carbonyl group?

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Oxygen is smaller in size than carbon. Hence the The C=O bond length (123pm) is shorter than the C=C bond length (134pm).

The carboxyl (-COOH) group consists of a ____ group attached to a ____ group; hence its name carboxyl.

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The carboxyl (-COOH) group consists of a carbonyl group attached to a hydroxyl group; hence its name carboxyl.

Aldehydes and ketones undergo ____.

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Aldehydes and ketones undergo nucleophilic addition reactions.

In numbering the carbon chain, the ____ is numbered one.

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In numbering the carbon chain, the carboxylic carbon is numbered one. Example: In CH3COOH, C of COOH is C1 and C of CH3 is C2.

Higher members of aliphatic carbonyl compounds (C12 – C18) that occur in natural fats as esters of glycerol are known as ____.

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Higher members of aliphatic carbonyl compounds (C12 – C18) that occur in natural fats as esters of glycerol are known as fatty acids. A fatty acid is a carboxylic acid with a long unbranched aliphatic tail (chain), which is either saturated or unsaturated.

In IUPAC system, aliphatic carboxylic acids are named by replaced the ending ____ in the name of the corresponding alkaline with ____ acid.

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In IUPAC system, aliphatic carboxylic acids are named by replacing the ending -e in the name of the corresponding alkaline with -oic acid. Example: Butane to Butanoic acid (-e is replaced with -oic acid), Methane to methanoic acid (-e is replaced with -oic acid).

Collins reagent is ____.

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Collins reagent is CrO3.2 C5H5N. Collins reagent is prepared by mixing pyridine and chromate in dichloromethane. Collins reagent and pyridinium chlorochromate are mild oxidising agents which can convert primary alcohols to aldehydes and secondary alcohols to ketones. The advantage of these reagents is that with these reagents, oxidation stops at the aldehydes stage preventing further oxidation of aldehydes to carboxylic acids. These reagents also do not attack double bonds.

Aliphatic carboxylic acids up to ____ carbon atoms are colourless liquids at room temperature, with ____ odours.

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Aliphatic carboxylic acids up to nine carbon atoms are colourless liquids at room temperature, with unpleasant odours.

According to IUPAC system, HCOO-CH2-CH(COOH)-CH2-COOH is ____.

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According to IUPAC system, HCOO-CH2-CH(COOH)-CH2-COOH is propane-1,2,3-tricarboxylic acid. There are 3 alkyl carbons, so propane. There are 3 - COOH attached to C1, C2 and C3, so 1, 2, 3 - tricarboxylic acid. The number of carboxylic groups are indicated by adding the multiplicative prefix, di, tri, etc. to the term oic. The position of - COOH groups are indicated by the Arabic numerals before the multiplicative prefix. In this case 1, 2, 3 -.

____, the simplest aromatic caboxylic acid is nearly insoluble in ____.

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Benzoic acid, the simplest aromatic caboxylic acid is nearly insoluble in cold water.

Higher carboxylic acids are practically ____ in water.

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Higher carboxylic acids are practically insoluble in water, due to the increased hydrophobic interaction of hydrocarbon part.

Acetaldehyde is used primarily as a starting material in the manufacture of all the substances given below other than ____.

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Acetaldehyde is used primarily as a starting material in the manufacture of all the substances given below other than benzene. Benzene is a pure aromatic hydrocarbon.

In aldehydes, the carbonyl group is on the ____ of a carbon chain, while in ketones, it is in the ____of a carbon chain.

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In aldehydes, the carbonyl group is on the end of a carbon chain, while in ketones, it is in the middle of a carbon chain. In aldehydes, the carbonyl group has a hydrogen atom attached to it and is the end of the chain.

Some higher members of ____ carboxylic acids (C12 - C18) known as ____, occur in natural fats as esters of glycerol.

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Some higher members of aliphatic carboxylic acids (C12 - C18) known as fatty acids, occur in natural fats as esters of glycerol.

Carbonyl groups add flavour and fragrance to nature in the forms given below except ____.

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Carbonyl groups add flavour and fragrance to nature in the forms given, except formic acid. Formic acid or methanoic acid was first obtained from red ants (Latin: formica means ant). Instead of flavour and fragrance, it gives the sting which all of us have experienced.

Formic acid (HCOOH) was first obtained from ____.

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Formic acid (HCOOH) was first obtained from red ants (Latin: formica means ant).

What makes butanone less volatile as compared to ethoxy ethane?

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Butanone is less volatile because of the presence of stronger dipole- dipole interactions. These interactions are stronger than the Van der waal’s interactions present in ethoxy ethane.

Acetic acid (CH3COOH) was obtained from ____.

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Acetic acid (CH3COOH) was obtained from vinegar (Latin: acetum, means vinegar).

Simple aliphatic carboxylic acids having up to ____ carbon atoms are ____ in water

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Simple aliphatic carboxylic acids having up to four carbon atoms are miscible in water due to the formation of hydrogen bonds with water.

Arrange CH3CHO, CH3CH2OH, CH3CH2CH3 and CH3OCH3 in the increasing order of their boiling points are ____.

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CH3CH2OH is highly associated due to hydrogen bonding. In CH3CHO, there is no hydrogen bonding but only dipole- dipole interactions. As CH3CHO is more polar than CH3OCH3 the magnitude of dipole- dipole interactions is more in CH3CHO. In CH3CH2CH3 there is presence of only weak Van der waal’s forces of attraction. Hence the order of increasing boiling points is CH3CH2CH3 <CH3OCH3 <CH3CHO <CH3CH2OH.

Class 12th Chemistry - 12 Aldehydes, Ketones and Carboxylic acids MCQs
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Class 12th Chemistry - 12 Aldehydes, Ketones and Carboxylic acids MCQs