Question #1c86b

We recall that:

#"Molarity" = "mols solute"/"L solution"#

Define a general polyprotic acid, #"H"_n"A"#, whose complete dissociation would be represented as:

#"H"_color(red)(n)"A" + color(red)(n)"H"_2"O"(l) -> color(red)(n)"H"_3"O"^(+)(aq) + "A"^(color(red)(n)-)(aq)#

where #n# is the number of protons in the acid.

Then, its normality is:

#" "ul(" "" "" "" "" "" "" "" "" "" "" "" "" "" ")#
#" "ulbb(|" ""Normality" = color(red)(n) xx "Molarity"" "| )#

In a context that you might actually use, consider a polyprotic acid, such as #"H"_3"PO"_4#.

For example, if we have a #"1 M"# molarity, then we actually have a #"3 N"# normality, because it takes #"3 mol"#s of #"OH"^(-)# to neutralize #"1 mol"# of #"H"_3"PO"_4#.

Or, define a general hydroxide-containing strong base, #"B"("OH")_n# (where #"B"# is the base, not boron). Then, its complete dissociation would be represented as:

#"B"("OH")_(color(red)(n))(aq) -> "B"^(color(red)(n)+)(aq) + color(red)(n)"OH"^(-)(aq)#

Then, its normality is also as defined above.

For example, if we have a #"2 M"# molarity of #"Ba"("OH")_2#, then we actually have a #"4 N"# normality, because it takes #"4 mol"#s of #"H"^(+)# to neutralize #"2 mols"# of #"Ba"("OH")_2#.

As a note, the normality unit is discouraged by IUPAC and NIST due to its ambiguity and dependence on context.