Per acetic acid ( CH3COOO-H ) is a weaker acid than acetic acid as acetate ion is stabilised by resonance .
Acidic strength of aromatic acids The parent member of the family benzoic acid which is a weaker acid ( Ka = 6.3 x 10 -5 ) than acid ( Ka = 17.7 x 10 -5 ) but stronger than acetic acid .
Some order of acidity are
( b ) Similarly , Ka values of methyl substituted ( toluic acids ) at 298 K are as follows :
From the Ka values , it is evident that with the exception of o-isomer , both p and m-toluic acids are weaker acids than benzoic acid whereas the three isomeric nitro benzoic acids are stronger acids than benzoic acid .
( ii ) Reactions involving cleavage of C-O-H bond ( a ) Formation of anhydride