Question

An aqueous solution of barium hydroxide is standardized by titration with a 0.134 M solution of hydrobromic acid. If 22.0 ml of base are required to neutralize 21.8 ml of the acid, what is the molarity of the barium hydroxide solution?

? M barium hydroxide

Answer 1

Sol.

Reaction of barium hydroxide , Ba(OH)2 with hydrobromic acid , HBr :  

Ba(OH)2 + 2HBr -----> BaBr2 + 2H2O

As Molarity of HBr = 0.134 M

Volume of HBr = 21.8 mL  

So , Millimoles of HBr = Molarity of HBr × Volume of HBr

= 0.134 M × 21.8 mL

= 2.9212 mmol

From reaction ,  

Millimoles of Ba(OH)2 = Millimoles of HBr / 2

= 2.9212 mmol / 2 = 1.4606 mmol

As Volume of Ba(OH)2 = 22 mL

Therefore , Molarity of Ba(OH)2  

= Millimoles of Ba(OH)2 / Volume of Ba(OH)2

= 1.4606 mmol / 22 mL

=    0.066 M