Question

What is the approximate pH at the equivalence point of a weak acid-strong base titration if 25 mL of aqueous formic acid requires 29.80 mL of 0.3567 MNaOH? Ka = 1.8×10−4 for formic acid.

Answer 1

Answer:

pH= 0.369

Explanation:

The formic acid reacts with NaOH as

HCOOH + NaOH= HCOONa + H2O

Apply CaVa/ CbVb = Na/Nb

Ca×25/(29.8×0.3587) = 1/1

Ca= (29.8×0.3587)/25= 0.428M

pH = - log(H+)

Since only 0ne H+ is in the stoichiometric equation, it means H+ = 0.428M

pH = -log(0.428) =0.369

Answer 2

Explanation:

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