Question

how many mL of 0.5M HCI is needed to neutralize 500mL and 0.2M Ba(OH)2?

Answer 1

Molarity of Ba(OH)2 = number of moels of Ba(OH)2 / volume of solution in L

0.2 M = number of moles of Ba(OH)2 / 0.500 L

Number of moles of Ba(OH)2 = 0.1 mole

balanced equation is

Ba(OH)2 + 2 HCl -----> BaCl2 + 2H2O

from the balanced equation we can say that

1 mole of Ba(OH)2 requires 2 mole of HCl so

0.1 mole of Ba(OH)2 will require 0.2 mole of HCl

Molarity of HCl = number of moels of HCl / volume of solution in L

0.5 = 0.2 / volume of HCl in L

Volume in L = 0.4 L

1 L = 1000 mL

so 0.4 L = 400 mL

Therefore, the volume of HCl is 400 mL