Name the compounds whose line formulae are given below.
Write structural formulae for compounds named as
(a) 1-bromoheptane
(b) 5-bromoheptanoic acid
Draw the resonance structures of the following compounds.
Identify the most stable species in the following set of ions giving reasons
(a) $\stackrel{+}{\mathrm{C}} \mathrm{H}_3, \stackrel{+}{\mathrm{C}} \mathrm{H}_2 \mathrm{Br}, \stackrel{+}{\mathrm{C}} \mathrm{HBr}_2, \stackrel{+}{\mathrm{C}} \mathrm{Br}_3$
(b) $\stackrel{\ominus}{\mathrm{C}} \mathrm{H}_3, \stackrel{\ominus}{\mathrm{C}} \mathrm{H}_2 \mathrm{Cl}^{\mathrm{C}} \stackrel{\ominus}{\mathrm{C}} \mathrm{HCl}_2, \stackrel{\ominus}{\mathrm{C}} \mathrm{Cl}_3$
(a) $\stackrel{+}{\mathrm{C}} \mathrm{H}_3$ is the most stable species because the replacement of H by Br increases positive charge ( $-I$-effect) on carbon atom and destabilises the species and, more the number of Br -atoms, less stable is the species.
(b) $\stackrel{\ominus}{\mathrm{C}} \mathrm{Cl}_3$ is the most stable species because on replacing H by Cl , negative charge on carbon is dispersed due to $-I$-effect of Cl and thus get reduced and species is stabilised. Further, more the number of Cl atoms, more is the dispersal of the negative charge and hence more stable is the species.
Give three points of differences between inductive effect and resonance effect.
Difference between inductive effect and resonance effect is as follows
| Inductive effect | Resonance effect |
|---|---|
| Inductive effect involves $\sigma$ - electrons displacement and occurs only in saturated compounds. | It involves $\pi$ - electrons or lone pair of electrons and occurs only in unsaturated and conjugated system. |
| Inductive effect can move upto 3 - carbon atoms. | It is applicable all along the length of conjugated system. |
| In inductive effect, there is a slight displacement of electrons and thus only partial positive and negative charges appear. | In resonance effect, there is complete transfer of electrons and thus full positive and negative charges appear. |