Acetic acid differs from formic acid in that

Acetic acid differs from formic acid in that
  1. acetic acid is stable to heat
  2. formic acid is stable to heat
  3. acetic acid acts as a reducing agent
  4. acetic acid shows positive test with Tollens reagent

Solution

Acetic acid is thermally more stable than formic acid.
Formic acid is more acidic than acetic acid because the elimination of $\mathrm{H}+$ ion is not opposed by any group and obtained formate ion is resonance stabilized.
In Acetic acid, the elimination of $\mathrm{H}+$ ion is opposed by $+$ leffect of - CH3 group attached to $-\mathrm{COOH}$ group. *

Asked in: JEE-TOPICTESTS-CHEMISTRY

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