Question

The H3O concentration of HCL is 2 x 10 ^-10 M, what is the pH?

10.5
9.7
4.5

Answer 1

If HCl is a strong acid - meaning it dissociates 100% - then use \(\sf pH=-log[H_3O^+]\)

Answer 2

The pH is equivalent to the -log of the H+ concentration.

pH = -log[H+]

The P in-front of the H means take the -log of something.

-log[2x10^-10]

Remember pH is a relative term, just says the concentration of H+ ions in a solution, but doesn't give you the sense how strong an acid is, for that we use Ka values.

Answer 3

i agree with both.

Answer 4

I put it in the calculator and got 9.6989 so I'm assuming that's the answer, thanks guys :)

Answer 5

Yes 9.69 is the answer! And remember the product of [H+][OH-] = 10^-14