(a) What is meant by the following terms ? Give an example of the reaction in each case. `(i)"Aldol"" "(ii)"Semicarbazone"`
(b) Complete the following :
(i) `CH_(3)COCl overset(H_(2)Pd-BaSo_(4))to`
`(ii) CH_(3)-CH=CH-CNoverset(DIBAl-H)to`

Explanation

(i) Aldol: `beta` - hydroxy aldehyde or ketones are collectively called aldol. Aldehyde and ketones having `alpha-` hydrogen undergo condensation in the presence of dil NaOH to from aldol is called aldol condensation.
For example : `2CH_(3)overset("dilNaOH")tounderset("3-hydroxy butanol (Aldol)")overset(OH)overset(|)(CH_(3)CH-CH_(2)CHO)`
(ii) Semicarbazone: When carbonyl group of aldehyde or ketone undergo nucleophilic addition reaction with semicarbbazide to give the product semi carbazon.

(b) Complete the followong : (i) `CH_(3)COCl +H_(2)underset(BaSO_(4))overset(Pb)toCH_(3)CHO+HCl`