Question

A certain volume of 2.0 M KOH solution is used to completely react with an excess of 0.10 L of 3.0 M HBr solution to produce 7.5 g of KBr. What are volumes (in litre) of KOH volume needed in the reaction and volume of HBr solution actually needed to completely react with KOH?

Answer 1

Ans :

The balanced reaction is given as :

HBr + KOH = KBr + H2O

Number of mol KBr = mass / molar mass

=7.5 g / 119 g/mol = 0.063 mol

So mol KOH and HBr required will be : 0.063 mol

Molarity KOH = mol KOH / volume KOH (L)

2.0 M = 0.063 mol / V

V = 0.0315 L

so volume of KOH needed = 0.0315 L

Molarity HBr = mol HBr / volume HBr (L)

3.0 M = 0.063 mol / V

V = 0.021 L

so volume of HBr needed = 0.021 L