NEET Chemistry Questions: Basic Principles of Orgainc Chemistry

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The type of delocalisation involving sigma bond orbitals is called




The type of delocalization involving sigma bond orbitals is called hyperconjugation. Hyperconjugation is the interaction of sigma electrons (usually C-H or C-C) with an adjacent empty or partially filled p-orbital or a π-orbital to give an extended molecular orbital. This effect is also known as no-bond resonance.
Arrangement of $(CH_3)_3C–, (CH_3)_2CH –, CH_3 – CH_2 –$ when attached to benzyl or an unsaturated group in increasing order of inductive effect is




The inductive effect is the electron-withdrawing or electron-donating effect transmitted through sigma bonds. The order of inductive effect is based on the alkyl groups' ability to donate electrons through sigma bonds. The correct order of increasing inductive effect for the given groups is $CH_3–CH_2 – < (CH_3)_2CH – < (CH_3)_3C –$ because the inductive effect increases with the number of alkyl groups attached to the carbon atom.
The correct order of increasing basic nature for the bases $NH_3, CH_3NH_2 and (CH_3)_2NH$ is:




The basic nature of amines depends on the availability of the lone pair of electrons on the nitrogen atom for protonation. In ammonia ($NH_3$), there is no alkyl group attached to the nitrogen, so its basicity is the lowest. In $CH_3NH_2$ (methylamine), the electron-donating effect of the methyl group increases the electron density on the nitrogen, making it more basic than ammonia. In $ (CH_3)_2NH$ (dimethylamine), two electron-donating methyl groups further increase the electron density on nitrogen, making it the most basic among the three. Therefore, the correct order of increasing basic nature is $ NH_3 < CH_3NH_2 < (CH_3)_2NH$.
Which of the following compounds will show metamerism




Metamerism is a type of isomerism where compounds have the same molecular formula but different alkyl groups on either side of a functional group. $C_2H_5 - S - C_2H_5$ (diethyl sulfide) can show metamerism because changing the alkyl groups on either side of the sulfur atom can result in different compounds like $CH_3 - S - C_3H_7$. The other options do not show metamerism because changing the alkyl groups on either side of the functional group does not result in different compounds.
In the reaction a chiral centre is produced. This product would be




When a chiral center is produced in a reaction, it typically results in the formation of a racemic mixture, which is an equimolar mixture of the two enantiomers (dextrorotatory and laevorotatory forms). This is because the reaction does not preferentially produce one enantiomer over the other, leading to a mixture that is optically inactive as the rotations cancel each other out.
Cyclic hydrocarbon molecule ‘A’ has all the carbon and hydrogen in a single plane. All the carbon-carbon bonds are of same length less than $1.54 A^\circ $ , but more than $1.34 A ^\circ $ . The bond angle will be




The given information suggests that the hydrocarbon molecule 'A' is a planar cyclic structure where all the carbon-carbon bonds are of equal length between 1.34 Å (which is typical for double bonds) and 1.54 Å (which is typical for single bonds). This implies that the bonds are likely to be somewhere in between, hinting at possible resonance structures. A common example fitting this description is benzene, which is a planar cyclic molecule with bond angles of $120^ ext{°}$ due to its $sp^2$ hybridized carbon atoms.

Isobutyl chloride is:





(b) It should contain (CH3)2CH- group to be named as iso.

IUPAC name of, CH3CH(OH)CH2CH2COOH is:





(a) Follow IUPAC rules.

IUPAC name of the compound, ClCH2CH2COOH is:





(a) Follow IUPAC rules.

In IUPAC suffix name of -COX is:





(a) Follow IUPAC rules.

IUPAC name of C6H5CN is:





(b) Follow IUPAC rules.

A reagent suitable for the determinatin of N-terminal residue of a peptide is 





(d) 2,4-dinitro fluorobenzene is called Sanger's reagent. When this reagent reacts with amino group of peptide chain, it form 2,4-dinitrophenyl derivatives which on hydrolysis form DNP derivatives of amino acids.

The dihedral angle between two C-H bonds in the staggered conformation of ethane  is            





No explanation available.

Isomers of a substance must have the same         





(d) Two or more compounds having the same molecular but different physical, chemical properties and structural formula are called isomers.

But-2-ene exhibits cis-trans-isomerism due to





 Due to presence of >C=C< in butene-2, it shows restricted rotation. Hence, give two types of arrangements around the space of >C=C< as cis and trans-forms.