The pH of a 2M solution of NaOH is...? (please include the complete solution of the problem)
1 Answer
Explanation:
For starters, you should know that an aqueous solution at room temperature has
#color(blue)(ul(color(black)("pH + pOH = 14")))#
This means that you express the
#"pH" = 14 - "pOH"#
Now, the
#color(blue)(ul(color(black)("pOH" = - log(["OH"^(-)]))))#
This means that the
#"pH" = 14 - [- log(["OH"^(-)])]#
#"pH" = 14 + log(["OH"^(-)])" "color(darkorange)("(*)")#
As you know, sodium hydroxide is a strong base, which implies that it ionizes completely in aqueous solution to produce sodium cations and hydroxide anions.
You can thus say that
#"NaOH"_ ((aq)) -> "Na"_ ((aq))^(+) + "OH"_ ((aq))^(-)#
Since every
#["OH"^(-)] = ["NaOH"]#
In your case, this is equal to
#["OH"^(-)] = "2 M"#
Plug this into equation
#"pH" = 14 + log(2) = color(darkgreen)(ul(color(black)(14.3)))#
The answer is rounded to one decimal place, the number of sig figs you have for the concentration of the solution.
As a final note, don't get confused by the fact that you have
#"pH" > 14#
This is what you'll always get for basic solutions that have
and it means that