Question #b992c
1 Answer
Explanation:
This one is pretty straightforward, meaning that all you have to do here is use the definition of the pH.
As you know, the pH of a solution is simply a measure of how many hydronium cations,
By definition, the pH is equal to
#color(blue)(bar(ul(|color(white)(a/a)color(black)("pH" = - log(["H"_3"O"^(+)]))color(white)(a/a)|)))#
Now, the problem provides you with the pH and asks for the corresponding concentration of hydronium cations.
To figure that out, rewrite the equation as
#-"pH" = log(["H"_3"O"^(+)])#
Use both sides of the equation as powers of
#10^(-"pH") = 10^(log(["H"_3"O"^(+)]))#
This is equivalent to
#["H"_3"O"^(+)] = 10^(-"pH")#
Plug in your value to find
#["H"_3"O"^(+)] = 10^(-8.24) = 5.8 * 10^(-9)"M"#
TYhe answer is rounded to two sig figs because you have two decimal places for the pH value.
The
As you know, a neutral solution kept at room temperature has
#"pH" = 7#
That value corresponds to
#["H"_ 3"O"^(+)]_"neutral sol" = 1.0 * 10^(-7)"M"#
Solutions that have pH values
In your case,
#"pH" = 8.24 > "pH" = 7#
and
#5.8 * 10^(-8)"M" < 1.0 * 10^(-7)"M"#