To calculate the pKa of the weak acid, we use the Henderson-Hasselbalch equation. It is expressed as pH = pKa - log [HA]/[A-]. This equation takes into account the concentration of the substance that does not dissociates into ions since it is a weak acid. We caculate as follows:
pH = pKa - log [HA]/[A-]
9 = pKa - log 1/100
pKa = 7
This means that they mixed .
You would do 82.75 divided by 125 cm3 and get 0.6620 g/cm3 because to find density you mist divide mass and volume and grams is always mass and cm3 or mL is always volume. hope i helped!
These substances can be separated by distillation, so your answer is A.
