Organic Chemistry Basics MCQs 2026

The simplest alkane is

1. A ethane ✓
2. B methane ✓
3. C propane ✓
4. D butane ✓

The general formula of alkanes is

1. A CnH2n+2 ✓
2. B CnH2n ✓
3. C CnH2n-2 ✓
4. D CnHn ✓

Alkanes are ___ hydrocarbons.

1. A unsaturated ✓
2. B aromatic ✓
3. C saturated ✓
4. D cyclic only ✓

The molecular formula of methane is

1. A C2H6 ✓
2. B C2H4 ✓
3. C CH2 ✓
4. D CH4 ✓

Alkenes contain at least one carbon-carbon

1. A single bond ✓
2. B triple bond only ✓
3. C ionic bond ✓
4. D double bond ✓

The general formula of alkenes is

1. A CnH2n+2 ✓
2. B CnH2n ✓
3. C CnH2n-2 ✓
4. D CnHn ✓

The simplest alkene is

1. A ethene ✓
2. B methene ✓
3. C propene ✓
4. D butene ✓

Alkynes contain a carbon-carbon

1. A single bond ✓
2. B double bond ✓
3. C triple bond ✓
4. D ionic bond ✓

The general formula of alkynes is

1. A CnH2n+2 ✓
2. B CnH2n ✓
3. C CnHn ✓
4. D CnH2n-2 ✓

The simplest alkyne, also called acetylene, is

1. A methyne ✓
2. B ethyne ✓
3. C propyne ✓
4. D butyne ✓

A series of compounds with the same general formula differing by CH2 is a

1. A homologous series ✓
2. B periodic group ✓
3. C isotope series ✓
4. D radical ✓

The functional group -OH represents

1. A an acid ✓
2. B an aldehyde ✓
3. C an alcohol ✓
4. D a ketone ✓

The functional group -COOH is characteristic of

1. A alcohols ✓
2. B ketones ✓
3. C esters ✓
4. D carboxylic acids ✓

The functional group of aldehydes is

1. A -CHO ✓
2. B -OH ✓
3. C -COOH ✓
4. D -NH2 ✓

Hydrocarbons are compounds containing only carbon and

1. A oxygen ✓
2. B nitrogen ✓
3. C hydrogen ✓
4. D chlorine ✓

Carbon has a valency of

1. A 2 ✓
2. B 4 ✓
3. C 6 ✓
4. D 1 ✓

The element that forms the backbone of all organic compounds is

1. A carbon ✓
2. B hydrogen ✓
3. C sulfur ✓
4. D iron ✓

Organic chemistry is mainly the study of compounds of

1. A nitrogen ✓
2. B oxygen ✓
3. C silicon ✓
4. D carbon ✓

The -NH2 functional group is found in

1. A alcohols ✓
2. B amines ✓
3. C acids ✓
4. D ketones ✓

Ethanol belongs to the family of

1. A alkanes ✓
2. B acids ✓
3. C alcohols ✓
4. D esters ✓

Which of the following is an alcohol

1. A methane ✓
2. B methanol ✓
3. C methanal ✓
4. D methanoic acid ✓

The main constituent of natural gas is

1. A methane ✓
2. B ethene ✓
3. C ethanol ✓
4. D benzene ✓

The suffix "-oic acid" in IUPAC naming indicates a

1. A carboxylic acid ✓
2. B alcohol ✓
3. C ketone ✓
4. D aldehyde ✓

Benzene is an example of a(n) ___ hydrocarbon.

1. A saturated straight-chain ✓
2. B simple alkane ✓
3. C aromatic ✓
4. D alkyne ✓

The molecular formula of ethene is

1. A C2H6 ✓
2. B C2H4 ✓
3. C C2H2 ✓
4. D CH4 ✓

The reaction in which alkenes join into long chains called polymers is

1. A combustion ✓
2. B neutralisation ✓
3. C polymerisation ✓
4. D hydrogenation ✓

The molecular formula of ethyne (acetylene) is

1. A C2H6 ✓
2. B C2H4 ✓
3. C CH4 ✓
4. D C2H2 ✓

Compounds with the same molecular formula but different structures are called

1. A isotopes ✓
2. B allotropes ✓
3. C polymers ✓
4. D isomers ✓

The process of adding hydrogen across a double bond is called

1. A hydrogenation ✓
2. B oxidation ✓
3. C neutralisation ✓
4. D fermentation ✓

Saturated compounds contain only ___ bonds between carbon atoms.

1. A double ✓
2. B single ✓
3. C triple ✓
4. D ionic ✓

The IUPAC name of CH3-CH3 is

1. A methane ✓
2. B propane ✓
3. C ethane ✓
4. D butane ✓

Vinegar is a dilute solution of

1. A ethanol ✓
2. B methanol ✓
3. C formic acid ✓
4. D acetic acid ✓

The number of carbon atoms in propane is

1. A 2 ✓
2. B 3 ✓
3. C 4 ✓
4. D 5 ✓

Complete combustion of hydrocarbons in plenty of oxygen produces carbon dioxide and

1. A water ✓
2. B hydrogen ✓
3. C methane ✓
4. D carbon ✓

The ability of carbon to bond with itself forming long chains is called

1. A isomerism ✓
2. B hydrogenation ✓
3. C polymerity ✓
4. D catenation ✓

The IUPAC prefix for a chain of four carbon atoms is

1. A meth- ✓
2. B prop- ✓
3. C but- ✓
4. D eth- ✓

Which is an unsaturated hydrocarbon

1. A methane ✓
2. B ethane ✓
3. C propane ✓
4. D ethene ✓

The IUPAC name of the alkane with three carbons is

1. A ethane ✓
2. B methane ✓
3. C propane ✓
4. D butane ✓

The functional group present in ketones is

1. A a carbonyl (C=O) between two carbons ✓
2. B -OH ✓
3. C -COOH ✓
4. D -NH2 ✓

A compound of carbon, hydrogen and oxygen with the -COOH group is a(n)

1. A alcohol ✓
2. B carboxylic acid ✓
3. C hydrocarbon ✓
4. D amine ✓

The tetravalency of carbon allows it to form

1. A four covalent bonds ✓
2. B one bond ✓
3. C ionic bonds only ✓
4. D no bonds ✓

Fermentation of sugar by yeast mainly produces ethanol and

1. A oxygen ✓
2. B carbon dioxide ✓
3. C hydrogen ✓
4. D methane ✓

Diamond and graphite are allotropes of

1. A silicon ✓
2. B hydrogen ✓
3. C oxygen ✓
4. D carbon ✓

The IUPAC suffix for alcohols is

1. A -ane ✓
2. B -ene ✓
3. C -ol ✓
4. D -al ✓

The IUPAC suffix used for alkenes is

1. A -ane ✓
2. B -yne ✓
3. C -ol ✓
4. D -ene ✓