Question

"Calculate the pH during the titration of 20.00 mL of 0.1000 M HF(aq) with 0.2000 M NaOH(aq) after 9.4 mL of the base have been added. Ka of hydrofluoric acid

Answer 1

Answer:

The answer is " 10.39"

Explanation:

Calculating acid moles:

$= 0.02000 \ L \times 0.1000 \ M \\\\= 0.002000$

Calculating NaOH moles:

$= 0.02012 \ L \times 0.1000 \ M \\\\= 0.002012$

calculating excess in OH-  Moles:

$= 0.002012 - 0.002000\\\\=0.000012$

calculating total volume:

$= 20.00 + 20.12\\\\ = 40.12 mL \\\\= 0.04012 L$

$[OH-]= \frac{0.000012} { 0.0472}$

           $=0.00025 M$

$pOH = - \log 0.00025$

        = 3.6

$pH = 14 - pOH$

      = 10.39