Chemistry

Organic Chemistry Fundamentals

287 Questions

Organic chemistry fundamentals cover the structure, properties, and reactions of carbon containing compounds. The questions explore functional groups, isomerism, homologous series, and basic reaction mechanisms. This forms the basis of general chemistry across multiple examination formats.

Functional groupsIsomerism typesHomologous seriesCycloalkanesOrganic monomers

Organic Chemistry Fundamentals Questions

Multiple choice

Which of the following statements is not correct about trans-C2H2Cl2?

  1. It has one C2 symmetry element.

  2. Structure of this molecule is non planar.

  3. Two chlorine atoms are opposite to each other.

  4. It has one horizontal plane.

  5. Point group of this molecule is C2h.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Correct option. Trans-C2H2Cl2 molecule is planar due to sp2 hybridisation.

Multiple choice

Which of the following is true about the structure of C2H2 molecule?

  1. Infinite number of vertical planes

  2. Infinite number of horizontal planes

  3. Non-linear structure

  4. C4 principal axis of rotation

  5. Two horizontal planes of symmetry
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Correct option. C2H2 is a symmetrical linear molecule. So, infinite number of vertical planes are there.

Multiple choice

Which of the following pairs of compounds do not represent pairs of constitutional isomers? A. Propanal and 1-Propanol B. 2-Methylbutane and pentane C. 2-Chlorohexane and 3-chlorohexane

Chose the correct code given below:

  1. A only

  2. B only

  3. C only

  4. A and B

  5. A, B and C
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Constitutional or Structural isomerism is a form of isomerism in which molecules with the same molecular formula have bonded together in different orders, i.e. they each have a different structural formula. ⇒ Propionaldehyde or propanal (CH3CH2CHO) is the organic compound with the molecular formula C6H6O. ⇒ 1-Propanol (CH3CH2CH2OH) is the organic compound with the molecular formula C6H8O.

Propanal and 1-Propanol molecular formula are different so they are not able to show the Constitutional or Structural isomerism.

Multiple choice

The simplest hydrocarbon is known as

  1. Ethane

  2. Methane

  3. Siliken

  4. Hexane

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Methane (CH4) is the simplest hydrocarbon, consisting of one carbon atom bonded to four hydrogen atoms. Ethane has 2 carbons, hexane has 6 carbons, and 'Siliken' appears to be a misspelling or nonexistent term.

Multiple choice

The two adjacent members of a homologous series differ by the group ____.

  1. -CH

  2. -CH2

  3. -CH4

  4. -CH3CH2
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

In a homologous series, each successive member differs by one -CH2- unit (called a methylene group) when moving up or down the series. This constant difference of 14 atomic mass units gives the series its characteristic incremental physical and chemical properties. -CH, -CH4, and -CH3CH2 are not the repeating units.

Multiple choice

What is the general formula of alkanes?

  1. CnH2n

  2. CnH2n+2

  3. CnH2n-2

  4. CnH2n-4
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Alkanes are saturated hydrocarbons with the general formula CnH2n+2, where each carbon atom forms four single bonds. For alkenes it's CnH2n, for alkynes it's CnH2n-2, and option D doesn't represent any standard homologous series. The '+2' accounts for the extra hydrogens needed for saturation.

Multiple choice

What is the general formula of alkenes?

  1. CnH2n

  2. CnH2n+2

  3. CnH2n-2

  4. CnH2n-4
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Alkenes are hydrocarbons with one carbon-carbon double bond. This reduces the hydrogen count by 2 compared to alkanes, giving the general formula CnH2n where n is the number of carbon atoms.

Multiple choice

The hydrocarbons containing 5 -16 carbon atoms are ____.

  1. gases

  2. liquids

  3. solids

  4. none of these
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Hydrocarbons with 5-16 carbon atoms (pentane to hexadecane range) are liquids at room temperature. They have sufficient molecular weight and intermolecular forces to exist as liquids, unlike smaller alkanes (gases) or much larger ones (solids).

Multiple choice

What is the general formula of alkynes?

  1. CnH2n+2

  2. CnH2n-2

  3. CnH2n

  4. CnH2n- 4
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Alkynes contain a carbon-carbon triple bond. This triple bond reduces the hydrogen count by 4 compared to alkanes (CnH2n+2), resulting in the general formula CnH2n-2 where n is the number of carbon atoms.