Question

Calculate the volume of 0.730-M NaOH solution needed to completely neutralize 58.9 mL of a 0.700-M solution of the monoprotic acid HBr.

__________ mL NaOH

Answer 1

NaOH + HBr NaBr + H₂O

Molarity = Moles/ Liter

Moles = Molarity x Liter

Number of moles of HBr = 0.7 M x (58.9/1000) L = 0.0412 moles

Here 1 mole of HBr reacts with 1 mole of NaOH

So, 0.0412 moles of HBr reacts with 0.0412 mole of NaOH

Again ,

Molarity = Moles / Liter

Liter = Moles / Molarity

So, volume (in L) = (0.0412 ) x (0.730) L

                            = 0.030 L = 30 mL

Answer is 30 mL of NaOH.