Question

A solution of ammonia has a pH of 11.8. What is the concentration of OH– ions in the solution?

1.00 x 10^-14 M
6.33 x 10^-3 M
1.58 x 10^-12 M
1.58 x 10^-4 M

Answer 1

pH+pOH=14

Answer 2

pOH=-log[OH-}

Answer 3

I don't get it lol

Answer 4

Ok. Can you find the pOH?

Answer 5

How do i find that?

Answer 6

Substitute pH=11.8 in pH +pOH=14 and solve for pOH.

Answer 7

2.2?

Answer 8

:)

Answer 9

Then what

Answer 10

Now, substitute that value into the next equation and solve for {OH-}

Answer 11

pOH=-log[OH-]

Answer 12

Do you know how to work with logs?

Answer 13

ehh, kinda not really xD

Answer 14

This log is the common log or log base 10.

Answer 15

2.2=-log[OH-]

Answer 16

-2.2=log[OH-]

Answer 17

i don't even have a calculator on me

Answer 18

Following me so far?

Answer 19

Yes

Answer 20

That's ok. You should have one on your computer.

Answer 21

To get rid of the log function on the [OH-], raise both sides to the power of 10.

Answer 22

so -2.2^10

Answer 23

\[10^{-2.2}=10^{\log[OH-]}\]

Answer 24

The other way around.

Answer 25

oh

Answer 26

10 raised to the common log of [OH-] is just [OH-]

Answer 27

kk

Answer 28

So, 10^-2.2=[OH-]

Answer 29

:)

Answer 30

So B.

Answer 31

Right!

Answer 32

Thank you so much if i post another could you help

Answer 33

I can try

Answer 34

No worries