What is the pH of a solution with a hydrogen-ion concentration of
4.2×10^-10 M

Question

nikato · Answer

ph=-log[H+]

Where [H+] is your concentration of H+

anonymous · Answer

Can you walk me through an example?

nikato · Answer

Do you have an example you want to work on?

anonymous · Answer

Not an particular one. Any is fine.

nikato · Answer

Well. If you have some problems on pH, we can work on it together. Or else I'll have to make up one right now and the numbers might not be too pretty, but will use same process

anonymous · Answer

Yeah I'm looking in my book I'll post one in a few.

nikato · Answer

Ok

anonymous · Answer

Here's one
What is the pH of a solution with a hydrogen-ion concentration of
$$4.2\times10^{-10}M$$

anonymous · Answer

So I know my known is
$$[H^{+}]=4.2\times 10^{-10}$$
and
our equation is
$$pH=-\log[H^{+}]$$
And my unkown is
pH=?

anonymous · Answer

So what do I do next?

nikato · Answer

Substitution
Plug in 4.2x10-10 in [H+]

And use calculator to solve

nikato · Answer

If you did it correct, you should get around 9.38

anonymous · Answer

So
$$pH=-\log[4.2\times 10^{-10}]$$
$$\log[H^{+}]=\log[4.2 \times 10^{-10}]$$
$$=-9.37675$$
$$pH=-(-9.38)$$
$$pH=9.38$$
And it's basic

nikato · Answer

100% correct!