Answer to Question #310277 in General Chemistry for sam

Question

A 20.0 mL solution of NaOH is neutralized with 32.5 mL of 0.200 M HBr. What is the concentration of the original NaOH solution?

Answer 1

Solution:

Balanced chemical equation:

NaOH + HBr → NaBr + H₂O

According to stoichiometry:

Moles of NaOH = Moles of HBr

or:

Molarity of NaOH × Volume of NaOH = Molarity of HBr × Volume of HBr

Therefore,

Molarity of NaOH = (Molarity of HBr × Volume of HBr) / Volume of NaOH

Molarity of NaOH = (0.200 M × 32.5 mL) / (20.0 mL) = 0.325 M

Molarity of NaOH = 0.325 M

Answer: The concentration of the original NaOH solution is 0.325 M