Question

How many milliliters of 0.270 M HBr are needed to titrate each of the following solutions to the equivalence point?

(a) 70.9 mL of 0.189 M RbOH mL

(b) 46.2 mL of 0.297 M CsOH mL

(c) 682.0 mL of a solution that contains 6.06 g of KOH per liter mL

Answer 1

equivalence point --> mol of base = mol of acid

then

a)

mmol of base = MV = 70.9*0.189 = 13.4001mmol of base

then we need 13.4001 mmol of acid

M = mmol/mL

mL = mmol/M = 13.4001/(0.27) = 49.63 ml

b)

similar

mmol of base = MV = 46.2*0.297= 13.7214 mmol of base

then we need 13.7214 mmol of acid

M = mmol/mL

mL = mmol/M = 13.7214/(0.27) = 50.82 ml

c)

[KOH] = mol/V

mol = mass/MW

then

[KOH] = mass/(MW*V) = 6.06/(56.1056 *0.682) = 0.1583

similar

mol of base = MV = 46.2*0.1583= 7.31346 mmol of base

then we need 7.31346mmol of acid

M = mmol/mL

mL = mmol/M = 7.31346/(0.27) = 27.086ml