Question

Calculate the ph of a solution formed by mixing 150.0 ml of 0.10 m hc7h5o2 with 100.0 ml of 0.30 m nac7h5o2. The ka for hc7h5o2 is 6.5 × 10-5.

Answer 1

Answer:

4.49

Explanation:

pKa = - log 6.5 x 10⁻⁵

pKa  =4.19

Given that :

Volume = 150 mL = 0.150 L

For solutions:

number of moles of acid = volume × concentration

number of moles of  acid = 0.150 L × 0.10 M = 0.0150

number of moles  of salt = 0.100 L × 0.30 M = 0.0300

total volume = 150 + 100

= 250 mL

= 0.250 L

Concentration = number of moles/ Volume

∴

For [salt] = 0.0300/ 0.250

= 0.12 M

For [acid] = 0.0150/ 0.250

=0.06 M

pH = 4.19 + log 0.12/0.06

=4.49