Alcohol Phenol And Ethers

This is a short answer type question as classified in NCERT Exemplar

The nitration of aromatic compounds occurs by using HSO₄ and HNO₃ which leads to the formation of  NO₂⁺ (nitronium ion) electrophile.

Due to the formation of  NO₂⁺ electrophile, we can say that nitration is an example of aromatic electrophilic substitution. The electron releasing group on the benzene ring increases the rate of nitration and vice-versa.

Phenol is more easily nitrated than benzene as the hydroxyl (-OH) group on the benzene ring is an electron releasing group which increases the electron density at the ortho and para position due to +R effect of -OH group. The nitration occurs at these electron rich sites by the attack of NO₂⁺ electrophile. 

This is a short answer type question as classified in NCERT Exemplar

The reaction of alcohol with the conc. HCl and ZnCl₂ (Lucas reagent) leads to the formation of a carbocation through SN¹  mechanism. The more stable the carbocation, the faster the reaction will be.

Tertiary carbocation is the most stable due to hyperconjugation and inductive effect then is the secondary alcohol and the primary alcohol is the least stable.

Stability of carbocation:

Tertiary carbocation > Secondary carbocation  > Primary carbocation 

According to stability of carbocation, the reactivity order of the alcohol is:

Tertiary alcohol > Secondary alcohol  > Primary alcohol 

Tertiary alcohol reacts immediately with Lucas reagent and shows turbidity, secondary alcohol does not show turbidity with Lucas reagent at room temperature but on heating turbidity appears and primary alcohol do not react with lucas reagent even on heating.

This is a short answer type question as classified in NCERT Exemplar

In  O? C? O, the dipole moment is zero, hence non-polar while in R—O—R the dipole moment is non-zero due to which it is polar.

The CO₂ is a linear molecule and the dipole moment is equal and in the opposite direction due to which the dipole moment is zero. While in R—O—R, has bent structure and lone pair of electrons due to which the net dipole moment is nonzero and hence, it is a polar molecule.

The CO₂ is a linear molecule and the dipole moment is equal and in the opposite direction due to which the dipole moment is zero. While in R—O—R, has bent structure and lone pair of electrons due to which the net dipole moment is nonzero and hence, it is a polar molecule.

This is a short answer type question as classified in NCERT Exemplar

The alcohol with molecular formula C₄H₁₀O is butanol has 4 isomers, these are:

(a) CH₃-CH₂CH₂-CH₂OH   (Butane-1-ol)

(b) CH₃-C^*H-CH₂-CH₃  (Butane-2-ol)

            |

          OH

(c) CH₃-CH-CH₂-OH         (2-methylpropane-1-ol)

            |

          CH₃

          CH₃

             | 

(d) CH₃- C-CH₃                     (2-methylpropan-2-ol)

             |

           OH

Only butane-2-ol has chiral carbon due to it being the alcohol with molecular formula C₄H₁₀O exhibits optical activity.