Answer:
The concentration of the unknown acid (HA) is 0.434M
The molar mass of HA is 13.3g/mole
Explanation:
DETERMINATION OF MOLARITY OF THE UNKNOWN ACID
CaVa/CbVb = Na/Nb
From the equation of reaction and at equivalence point, Na = Nb = 1
Therefore, CaVa = CbVb
Va (volume of acid solution) = 20mL = 20/1000 = 0.2L
Cb (concentration of KOH) = 0.715M
Vb (volume of KOH) = 12.15mL
Ca (concentration of acid) = CbVb/Va
Ca = 0.715M × 12.15mL/20mL = 0.434M
DETERMINATION OF MOLAR MASS OF HA
Number of moles of acid = concentration of acid × volume of acid solution in liters = 0.434 × 0.2 = 0.0868mole
Molar mass of HA = mass/number of moles = 1.153g/0.0868mole = 13.3g/mole
