What volume of 0.500 M #NaOH# is needed to neutralize 45.0 mL of 0.400 M #HCl#?

1 Answer
May 3, 2016

#NaOH(aq) + HCl(aq) rarr NaCl(aq) + H_2O(l)#

Explanation:

Clearly there is a 1:1 equivalence, and as a first step we calculate the number of moles of hydrochloric acid:

#45.0xx10^-3*Lxx0.400*mol*L^-1# #=# #1.80xx10^-2*mol" hydrochloric acid"#.

We find an equivalent molar quantity of sodium hydroxide:

#(1.80xx10^-2*mol)/(0.500*mol*L^-1)xx10^3*mL*L^-1# #=# #36.0*mL#.

This volume is reasonable, in that it is LESS than the volume of the less concentrated acid.