<PRE><B>Question 1140121</B>
If molarity of Hydronium concentration is x,
{{{pH=-log((x))}}}

{{{log((x))=-pH}}}


{{{highlight(x=10^(-pH))}}}------------Use this with a calculator!



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The hydrogen ion concentration of a hair rinse is about 2.1 * 10^-4 moles per liter. Find the pH. 
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You want  {{{-log((2.1*10^(-4)))}}}.</PRE>