Question

uppose you perform a titration of an unknown weak acid solution. You start with 4.00 mL of the weak acid and find that it takes 12.8 mL of 0.0500 M NaOH to reach the equivalence point. What is the concentration of the unknown weak acid solution?

Answer 1

Explanation:

It is known that at the equivalence point,

     Equivalent of acid = equivalent of base ......... (A)

and,     Equivalent = $\text{Molarity} \times n_{f} \times V$

Therefore, equivalent of acid is calculated as follows.

     Equivalent of acid = $M \times 1 \times 4$ .......... (1)

     Equivalent of base = $0.05 \times 1 \times 12.8$ ............ (2)

Hence, using equation (A) we will calculate the concentration as follows.

           $M \times 4 = 0.05 \times 12.8$

                       M = 0.16 M

Thus, we can conclude that concentration of the unknown weak acid solution 0.16 M.