Q. 135.0( 2 Votes )
Explain the follo
(i) Alcohols are more soluble in water than the hydrocarbons of comparable molecular masses due to the following reasons:
⇒ In alcohols, hydroxyl group (OH) is present which helps in the formation of hydrogen bonds between alcohol and water molecules.
Hence, alcohols are soluble in water.
⇒ On the other hand, in hydrocarbon there is no hydroxyl group is present and as a result hydrogen bonding is absent. Hence, hydrocarbon is less soluble in water than alcohol.
(ii) Ortho-nitrophenol is more acidic than ortho-methoxyphenol.
More easily the removal of proton takes place, higher will be its acidic strength
⇒ Electron-donating groups such as –CH3, -OCH3, -NH2, etc. decrease the acidity.
⇒ Electron-withdrawing groups such as –NO2, -CN, -SO3H, -COOH, -X(halogen), etc. increase the acidity of phenol.
⇒ Electron-withdrawing groups stabilizes the phenoxide ion by dispersing (decreases) the negative charge relative to phenol increase the acidic strength of phenols.
⇒ Electron-donating groups destabilizes the phenoxide ion by intensifying (increasing) the negative charge relative to phenol tend to decrease the acidic strength of phenols.
⇒ In ortho-methoxyphenol, CH3 group is present and as we know that CH3 group is an electron donating(releasing) group which decreases the acidic strength of phenol.
⇒ In ortho-nitrophenol, NO2 group is present. As we know that NO2 group is an electron withdrawing group which increases the acidic strength of phenol.
Thus, orhto-nitrophenol is more acidic than ortho-methoxyphenol.
(iii) Cumene is a better starting material for the preparation of phenol.
The reaction for the preparation of phenol from cumene is given below:
As we can see that cumene undergoes hydrolysis with an aqueous acid to from phenol and also a side product acetone which is itself an another important organic compound.
Thus, Cumene is a better starting material for the preparation of phenol.
Rate this question :