pH Question Help

[matty.k]

Q6. A volume of 180 mL of 1.0M HCL is added to 100mL of 1.0M NaOH. Find the pH of the resultant solution.

how would i go about this question, would i use the ionic product of water, cause i dont get it. its not from the book or anything its just some revision question that i got from a friend. cheers VN

[vexx]

Calculate the mol of each so there's:

0.180mol HCl + 0.100mol NaOH
1:1 ratio, so 0.100 mol of NaOH (all of it) reacts with 0.100 mol of HCl

Now there is 0.080 mol of HCl left over, this determines the pH.
Afterwards find the concentration of HCl using this mol which = concentration of H+ ions.
And then find the pH using -log[H+ concentration]

[simonhu81292]

lol....
got beaten by vexx again...
yeah ..
your answer should be pH of 0.5
or you could round it up to 1
VEXX!!!

[m@tty]

Well, this is how I think you could do it..









So the result is of in 280 ml of solution.

So concentration of is .

and pH is defined as .

So pH is .

Hence, to two significant figures, the pH is .

[matty.k]

oh ok thanks guys

[m@tty]

Do you have the answer?

[simonhu81292]

nah .... matty .. that should be correct...
you did the right way ..~~~

[m@tty]

Haha, that's good. I'm never confident with my answers in Chem.. I always think there's something I could have overlooked >.<

[matty.k]

yea it worked thanks a bunch m@tty