# What is an example of a neutralization practice problem?

May 7, 2014

What is the concentration of sodium hydroxide if it takes 43.21 mL of sodium hydroxide to neutralize 25.00 mL of 0.273 M hydrochloric acid?

For this problem we are looking for the concentration of Molarity of the base in a neutralization reaction.

Using the balanced chemical equation

$H C l + N a O H \to {H}_{2} O + N a C l$

The reaction uses one mole of sodium hydroxide for every one mole of hydrochloric acid.

The equation for equilibrium of a neutralization reaction is

${n}_{b} {M}_{a} {V}_{a} = {n}_{a} {M}_{b} {V}_{b}$

${n}_{a}$ = moles of acid
${n}_{b}$ = moles of base
${M}_{a}$ = Molarity of Acid
${V}_{a}$ = Volume of Acid
${M}_{b}$ = Molarity of Base
${V}_{b}$ = Volume of Base

${n}_{a}$ = 1 mole
${n}_{b}$ = 1 mole
${M}_{a}$ = 0.273 M
${V}_{a}$ = 25.00 mL
${M}_{b}$ = ???
${V}_{b}$ = 43.21 mL

$1 m o l \left(0.273 M\right) \left(25.00 m L\right) = 1 m o l \left(x M\right) \left(43.21 m L\right)$
$\frac{6.825 M m L}{43.21 m L} = x M$
$0.158 M = x$