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
