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

The molecule lacking a stereogenic center shows ---------------------- chirality.

  1. planar

  2. axial

  3. supramolecular

  4. inherent

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

Axial chirality is a special case of chirality in which a molecule does not possess a stereogenic center (the most common form of chirality in organic compounds) but an axis of chirality - an axis about which a set of substituents is held in a spatial arrangement that is not superposable on its mirror image. Axial chirality is most commonly observed in atropisomeric biaryl compounds wherein the rotation about the aryl-aryl bond is restricted.

Multiple choice

Which of the following statements is/are correct? A. 1-chloro-2, 3-pentadiene has no chiral carbon atoms, yet it is a chiral molecule. B. A newly discovered compound is through to be chiral but shows no rotation in a specific solvent. Does this mean that the compound is assuredly achiral? C. When a chiral molecule reacts to give a chiral molecule, the product is always racemic.

  1. Only A

  2. Only B

  3. Only C

  4. Both A and C

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

This statement is correct, because the molecule as whole is chiral, since this molecule and its mirror image are non-superimposable.

Multiple choice

Which of the following statements is/are wrong? A. 1-methoxypropane and 2-methoxyprpane are metamers. B. An optically inactive substance must be achiral. C. m-Chlorobromobenzene and m-bromochlorobenzene are isomers.

  1. Both A and B

  2. Both A and C

  3. Both B and C

  4. A, B, and C

  5. None of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

1-methoxypropane and 2-methoxyprpane are chain or position isomers, a racemic mixture shows no optical activity and m-chlorobromobenzene and m-bromochlorobenzene represents the same compound, so the statement A, B, and C all are incorrect. Thus, this option is correct.

Multiple choice

Assertion: 1, 2-propadiene exhibits optical isomerism. Reason: Its mirror image is non-superimposable.

  1. Both A and R are true and R is the correct explanation of A.

  2. Both A and R are true but R is NOT the correct explanation of A.

  3. A is true but R is false.

  4. A is false but R is true.

  5. Both A and R are false.
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

This option is correct because 1, 2-propadiene does not exhibits optical isomerism due to it contains axis of symmetry.

Multiple choice

Assertion: Stereoisomerisms which are not mirror images of each other are called diastereomers. Reason: Diastereomers may or may not be optically active.

  1. Both A and R are true and R is the correct explanation of A.

  2. Both A and R are true but R is NOT the correct explanation of A.

  3. A is true but R is false.

  4. A is false but R is true.

  5. Both A and R are false.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Since, diastereomers may or may not be chiral,  they may or may not be optically active. Thus, this option is correct.

Multiple choice

Assertion: CHBr=CHCl exhibits geometrical isomerism but CH2Br-CH2Cl does not. Reason: Presence of C=C is one of the conditions of geometrical isomerism.

  1. Both A and R are true and R is the correct explanation of A.

  2. Both A and R are true but R is NOT the correct explanation of A.

  3. A is true but R is false.

  4. A is false but R is true.

  5. Both A and R are false.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

CHBr=CHCl exhibits geometrical isomerism but CH2Br-CH2Cl does not, because the molecule may or may not contain a double bond, only restricted rotation about a bond give rise to geometrical isomerism. Thus, this option is correct.

Multiple choice

Match the following according to which the nomenclature of organic compounds is done ||||| |---|---|---|---| |1|Prefix|a|Number of carbon atoms| |2|Root word|b|Nature of bond| |3|Suffix|c|Functional group|

  1. 1 - a, 2 - b, 3 - c

  2. 1 - c, 2 - b, 3 - a

  3. 1 - b, 2 - a, 3 - c

  4. 1 - b, 2 - c, 3 - a

  5. 1 - a, 2 - c, 3 - b
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Yes, it is correct. Prefix is the Number of carbon atoms. Root word is the nature of bond i.e. double or single bond and suffix is the functional group attached.

Multiple choice

Which is the formula of chloroform?

  1. CH2Cl

  2. CHCl3

  3. CHCl5

  4. CO2
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Chloroform has the chemical formula CHCl3, containing one carbon, one hydrogen, and three chlorine atoms. CH2Cl is incomplete, CHCl5 is chemically impossible (carbon can only form 4 bonds), and CO2 is carbon dioxide.

Multiple choice

Assertion: Azulene is a non-benzenoid compound. Reason: It is planar, has a cyclic array of 10 π-electrons but does not contain benzene rings.

  1. Both A and R are true and R is the correct explanation of A.

  2. Both A and R are true but R is NOT the correct explanation of A.

  3. A is true but R is false.

  4. A is false but R is true.

  5. Both A and R are false.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This option is correct because azulene is a non-bezenoid aromatic compound and it contains 5 π-bonds or 10 π-electrons but does not contain benzene rings.

Multiple choice

Assertion: Cyclooctatetraene reacts with two equivalents of potassium to form a stable compound with formula 2K+ C8H82-. Reason: Cyclooctatetraene is non-aromatic but 2K+ C8H82- is aromatic.

  1. Both A and R are true and R is the correct explanation of A.

  2. Both A and R are true but R is NOT the correct explanation of A.

  3. A is true but R is false.

  4. A is false but R is true.

  5. Both A and R are false.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

This option is correct,  because Cyclooctatetraene reacts with two equivalents of potassium to form a stable compound with formula 2K+ C8H82- and 2K+ C8H82- is aromatic.

Multiple choice

Two hexoses were found to give the same osazone. Which one of the following statements is correct with respect to their structural relationship? A. The carbon atoms 1 and 2 in both have the same configuration. B. They are epimeric at C3. C. The carbon atoms 3, 4 and 5 in both have the same configuration.

  1. Only A

  2. Only B

  3. Only C

  4. Both A and B

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

This option is correct,  because osazone formation involves reactions at C1 and C2, therefore, if two hexoses form the same osazone, they must have the same configuration at C3, C4 and C5.

Multiple choice

The isomerism exhibited by C2H5-O-C2H5 and CH3-O-CH(CH3)2 is

  1. functional

  2. metamerism

  3. position

  4. chain

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

Both compounds are ethers with molecular formula C4H10O. Diethyl ether (C2H5-O-C2H5) and methyl isopropyl ether (CH3-O-CH(CH3)2) differ only in the alkyl groups attached to the oxygen atom. This is metamerism - a type of structural isomerism where the functional group remains the same but the alkyl groups on either side vary.

Multiple choice

Heating a mixture of calcium acetate and sodalime gives

  1. methane

  2. ethane

  3. acetic acid

  4. benzene

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

The dry distillation of calcium acetate with soda lime (NaOH + CaO) produces methane through decarboxylation. Each acetate ion loses CO2 to form a methyl group, which then combines with hydrogen from the reagents to give methane (CH4). This is a classic laboratory method for alkane synthesis.