Chem question on acid strength?

Question

Arrange four acids(Ethanoic acid,Chloroethanoic acid,methanoic acid,benzoic acid) in descending order of acid strength and explain the difference of their acid strength

Answer 1

Strongest to weakest:

Chloroethanoic acid (chloroacetic)
Methanoic acid (formic)
Benzoic acid
Ethanoic acid (acetic)

The presence of the chlorine on chloroacetic acid has an inductive effect; the chlorine is more electronegative, which pulls electron density of its carbon, which polarizes the C-C bond, which in turn more evens out the polarity of the C-O bond, making the H more acidic.

Methanoic is more acidic than ethanoic as methyl groups are electron-donating, making the hydroxy oxygen less electron-hungry and thus not making the hydroxy hydrogen as acidic.

Benzoic is more acidic than ethanoic as the ring has the ability to delocalize the negative charge that results from ionization, whereas ethanoic cannot.