Wednesday 22 August 2012


How does electronegativity relate to acidity in organic compounds?

List the following carboxylic acids in order of decreasing acidity:

CH3CHClCOOH, CH3CH2COOH, CH2BrCH2COOH, CH3CCl2COOH

Best Answer - Chosen by Voters

CH3CCl2COOH > CH3CHClCOOH > CH2BrCH2COOH > CH3CH2COOH

A very electronegative atom will attract the electrons towards itself. This will reduce the electron charge density of the OH bond in COOH group. It weakens the OH bond and it is able to donate the proton (H+) more easily and hence a stronger acid.

[Acid is a proton donor]

The electron withdrawing effect is stronger in Cl than in Br because Cl is more electronegative than Br.

The withdrawing effect is stronger if the electronegative atom is nearer to the COOH group.

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