Hydrocarbons

According to Huckel?s rule, the molecules which contain electrons are aromatic.

Ozonolysis involves the breaking of double bond and insertion of 0 atoms in place of double bond. Therefore, the structure of alkene. is as

The main conditions for exhibiting geometrical isomerism are
(i) presence of double bond.
(ii) presence of different groups on same double bonded carbon.
(iii) presence of at least one similar group on adjacent double bonded carbon atoms.

does not exhibit geometric isomerism due to presence of same group on double bonded carbon atom .

[a]
[ b]
[c]
[ d]

Cyclooctatetraene is not aromatic in nature. In cyclooctatetraene, delocalisation of electrons takes place but Huckel's rule is not followed. According to Huckel's rule, it should contains electrons but it contains only electrons.
electron (i.e., Huckel rule is not followed), hence it is not aromatic.

The activating substituents make the benzene ring more reactive towards electrophilic substitution reaction while the deactivating substituents make the benzene ring less reactive towards electrophilic substitution reaction. group is the most activating group which is present in aniline hence it is the most reactive towards electrophilic substitution reaction.

For an electrophilic aromatic substitution reaction chlorine is directing group and also electron withdrawing group.

Anti-Markownikoff addition is not observed in -butene because both the doubly bonded carbons have same number of hydrogen atoms i.e., the alkene is symmetrical.

The least stable conformation of cyclohexane is half chair conformation.

A Aniline directly does not show nitration because it oxidised by nitration (conc. ). So, to do the nitration it is necessary to protect amino group as

group is ortho and para directing due to resonance the electron density is more on ortho and para positions.

Allene,
Double bonds =
Single bonds =

Answer (b) Chair conformation

In Wurtz reaction, alkyl halides react with metallic sodium in presence o f dry ether to form symmetrical alkanes containing double the number o f carbon atoms present in the alkyl halide