Question

What is the pH of a 10^-4 M HCl solution?Answers to choose:•1•2•3•4

Answer 1

Hydrochloric acid is a strong acid. This means that in a solution all the H+ ions will be released. Also, one mole of HCl has one hydrogen atom, so we can assume that the concentration of HCl is equal to the concentration of H+ ions.

On the other hand, the definition of pH tells us:

`pH=-log\lbrack H^+\rbrack`

Where [H+] is the ions H+ concentration.

H+ concentration is 10^-4M. If we replace in the equation we will have:

`\begin{gathered} pH=-log10^(-4)M=4 \\ pH=4 \end{gathered}`

answer: The pH of the solution is 4