Is it okay to have a $"pH"$ above $14$ ?? Apparently $"1.05 M"$ $"NaOH"$ has a $"pH"$ above $14$ at $25^@ "C"$ .

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Is it okay to have a $"pH"$ above $14$ ?? Apparently $"1.05 M"$ $"NaOH"$ has a $"pH"$ above $14$ at $25^@ "C"$ .

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Answer 1 · 2016-06-07T00:23:26

A $"pH"$ above $14$ is totally fine. Despite what you may learn about a [common] $"pH"$ range of $0-14$ , it doesn't mean $"pH"$ can't be negative, or above $14$ .

Let's go through it again, just to see what I get in comparison.

A $"1.05 M"$ $"NaOH"$ solution has $"1.05 M"$ of dissociated $"OH"^(-)$ anions, since dissociating $"NaOH"$ generates an equimolar quantity of $"OH"^(-)$ :

$"NaOH"(s) stackrel("H"_2"O"(l)" ")(->) "Na"^(+)(aq) + "OH"^(-)(aq)$

So, the $"pOH"$ is

$"pOH" = -log["OH"^(-)]$

$= -0.0212$

Now recall that $"pH" + "pOH" = 14$ .

Hence, $color(blue)("pH" = 14 - "pOH" = 14.02 > 14.0)$ .

If you still are wondering, "really? It's true?", then perhaps reading this note from this website can reassure you:

"The pH scale does not have an upper nor lower bound."

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Is it okay to have a $"pH"$ above $14$ ?? Apparently $"1.05 M"$ $"NaOH"$ has a $"pH"$ above $14$ at $25^@ "C"$ .

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Is it okay to have a "pH""pH" above 1414?? Apparently "1.05 M""1.05 M" "NaOH""NaOH" has a "pH""pH" above 1414 at 25^@ "C"25^@ "C".

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Is it okay to have a $"pH"$ above $14$ ?? Apparently $"1.05 M"$ $"NaOH"$ has a $"pH"$ above $14$ at $25^@ "C"$ .