Question

How many milliliters of .405 Ba(OH)₂ solution are required to completely react with 17.5 milliliters of .244M HCl according to the balanced chemical equation? (your answer should have 3 significant figures and not include units)

2 HCl + Ba(OH)₂ --> 2 H₂O + BaCl₂

Answer 1

Number of moles of HCl = molarity * volume of solution in L

Number of moles of HCl = 0.244 * 0.0175 L = 0.00427 mole

From the balanced equation we can say that

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

0.00427 mole of HCl will require

= 0.00427 mole of HCl *( 1 mole of Ba(OH)2 / 2 mole of HCl)

= 0.00214 mole of Ba(OH)2

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

0.405 = 0.00214 / volume of solution in L

volume of solution in L = 0.00214 / 0.405 = 0.00528 L

1 L = 1000 mL

0.00528 L = 5.28 mL

Therefore, volume of Ba(OH)2 solution = 5.28 mL