group.
(ii) Reaction of aldehydes
having no
-H-atom.
(iii) Two different aldehydes
are condensed.
(iv) Removal of 
from
carboxyl group,
Answer:
(i) Acetvlation When active hydrogen atom of
alcohol,phenol or an amine is replaced by acetyl 
group to formcorresponding
ester or amide, the reaction is known asacetylation. Reagents used are acid
chloride or acid anhydride inpresence of a base like pyridine or dimethyl
aniline.
For example:
(ii) Cannizzaro reaction
Aldehydes which do not have any
-hydrogen
atom, undergo sell oxidation and reduction(disproportionation) reaction on
treating with concentrated alkali.
This reaction, is called
Cannizzaro reaction. As a result, onemolecule of aldehyde is reduced to alcohol
while another isoxidized to carboxylic acid salt.
For example:
(iii) Cross aldol condensation
When aldol condensation is carried outbetween two different aldehydes and or
ketones, it is called crossaldol condensation. If both the reactants contain -hydrogenatoms,
it gives a mixture of four products.
For example:
Please consult solution of Q. 9.
(iv) Decarboxylation Carboxylic
acids lose carbon, dioxide moleculeto produce hydrocarbons on heating their
sodium salts withsodalime (a mixture of NaOH and CaO in ratio 3:1). This
reactionis called decarboxylation.
For example:
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