Basic Principles of Orgainc Chemistry MCQs for NEET — Chemistry Questions with Answers

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 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$.

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.

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.

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.

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

(a) Follow IUPAC rules.

(a) Follow IUPAC rules.

(a) Follow IUPAC rules.

(b) Follow IUPAC rules.