(adsbygoogle = window.adsbygoogle || []).push({}); 1. The problem statement, all variables and given/known data

How would you prepare 5.00 L if an aqueous solution having a pH = 10.70, if you had a supply of 0.250 M NaOH?

2. Relevant equations

I don't even know anymore....

3. The attempt at a solution

I've tried a million different ways but I never come up with the answer provided in the book, which is 10 mL.

Here are two ways I've tried:

pH = 10.7; so pOH = 14.0-10.7 = 3.3

antilog (-3.3) = 5.0x10^-4 M

m1v1 = m2v2

v2 = m1v1 / m2 = (0.250 M x 5000 mL) / (5.0x10^-4) = 2500000 mL

That's DEFINITELY not right....

Second attempt:

5000 mL has x moles NaOH

5.0x10^-4 M / 5 L = 1x10^-4 moles NaOH

1x10^-4 mol NaOH x (40.0 g/mol) = 0.004 g NaOH

density of NaOH = 2.13 g/mL; so 0.004 g / 2.13 g/mL = 0.0018 mL

And that's not right either...

I'm missing SOMETHING and I've been working on this problem forever. Please help?

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# Homework Help: PH scale

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