Question #dcad3
1 Answer
Explanation:
We're asked to find the hydrogen ion concentration,
To do this, we can use the following relationship that is worth knowing:
#ul("pH" = -log["H"^+]#
Which we can rearrange to solve for the hydrogen ion concentration:
#ul(["H"^+] = 10^(-"pH")#
We're given that the
#["H"^+] = 10^-7.90 = color(red)(ulbar(|stackrel(" ")(" "1.3xx10^-8color(white)(l)"mol"*"L"^-1" ")|)#
Becuase the
The reason behind this comes from the fact that only the decimal places are important when calculating the logarithm. Basically, if the
#"pH" = -log(1.3xx10^-13color(white)(l)"mol"*"L"^-1) = 13#
if we only used two significant figures. This value isn't very precise, so we just use two decimal places:
#"pH" = 12.87#