Confused about a chemistry question answer!

I'm studying for final high school exams and I have a chem exam coming up in the next few days. I was doing the question 'What is the ph of a solution prepared by mixing 30.0mL of 0.10M nitric acid solution with 10.0mL of 0.10M barium hydroxide solution?'

What I did was:

Ba(OH)2 + 2HNO3 --> Ba(NO3)2 + 2H2O

moles Barium hydroxide= 0.01 x 0.1 = 0.001 moles

moles nitric acid= 0.1 x 0.03 = 0.003 moles

Therefore, nitric acid is in excess by 0.002 moles

Molarity excess nitric acid = 0.002/0.04L = 0.05 moles

pH is, therefore, -log(0.005) = 1.3

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Apparently, that's not right and the answer is meant to be 1.6.

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What the answer says is:

Ba(OH)2 + 2HNO3 --> Ba(NO3)2 + 2H2O

moles Barium hydroxide= 0.01 x 0.1 = 0.001 moles

moles nitric acid= 0.1 x 0.03 = 0.003 moles

Therefore, nitric acid is in excess.

moles excess nitric acid = 0.0030 - 0.0020 = 0.0010 moles

Molarity excess nitric acid = 0.001/0.04L = 0.025 moles

pH is, therefore, -log(0.025) = 1.6

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What am i doing wrong? Or what is the answer doing wrong? I've looked at this for so long that it's confusing me :S What I don't get is why the answer, when calculating the excess nitric acid moles, uses 0.0020 moles of barium hydroxide. Is that a typo? Or did i miss something in my calculation! ARGH!

"uses 0.0020 moles of barium hydroxide. Is that a typo?"

It's 0.0010 mol of Ba(OH)2. This is what is called the analytical concentration.

It's 0.00200 mol of hydroxide and only the hydroxide. (It's also 0.00100 mol of just barium ion.)

If your source says 0.00200 mol of Ba(OH)2, that's a typo.

Remember, there are two hydroxides released into solution for every one Ba(OH)2 that dissolves.

The actual excess moles of HNO3 is 0.001 because you need only TWICE as many moles of NO3 as you have Ba(OH)2. So if you have 0.001 mol of Ba(OH)2 then you only need 0.002 mol of HNO3.