For the compounds-I- HCOOH II- displaystyle CH-3-COOH III- displaystyle CH-3-CH-2-COOH IV- displaystyle C-6-H-5-COOH The correct order of decreasing acidity is -I - II - III - IVIV - I - II - IIIIV - II - III - II - IV - II - III

Question

Toppr Admin · Accepted Answer

To see the strength of acid here need to compare stability of conjugate bases of these acids. Higher $+ I$ effect of alkyl group $- C H_{3} C H_{2}$ makes $C H_{3} C H_{2} C O O^{-}$ least stable.

Presence of more electronegative atom stabilizes the negative charge.

$s p^{2}$ hybridized carbon shows a weaker $+ I$ effect as compared $s p^{3}$ carbon. Hence phenyl group is more electronegative as compared to $- C H_{3}$ (methyl group) but still less electronegative than hydrogen.

So, summarizing, the electronegativity order of the three substituents is $H > P h > C H_{3} > C H_{2} C H_{3}$ .

For the compounds,I) HCOOH II) CH3COOH III) CH3CH2COOH IV) C6H5COOH The correct order of decreasing acidity is :I > II > III > IVIV > I > II > IIIIV > II > III > II > IV > II > III

For the compounds,
I) HCOOH II) $C H_{3} C O O H$ III) $C H_{3} C H_{2} C O O H$ IV) $C_{6} H_{5} C O O H$
The correct order of decreasing acidity is :
I > II > III > IV
IV > I > II > III
IV > II > III > I
I > IV > II > III