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how many ml of a 0.10M NaOH solution are needed to neutralize 15 ml of 0.20 M H3PPO4...

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spikysplash | Student, College Freshman | (Level 1) eNoter

Posted December 5, 2011 at 9:32 AM via web

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how many ml of a 0.10M NaOH solution are needed to neutralize 15 ml of 0.20 M H3PPO4 solution?

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ndnordic | High School Teacher | (Level 2) Associate Educator

Posted December 6, 2011 at 12:55 AM (Answer #1)

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This is a neutralization reaction between phosphoric acid and sodium hydroxide.

First write a balanced chemical equation:

3 NaOH + H3PO4 --> Na3PO4 + 3 HOH

note that it takes 3 moles of base to completely neutralize the acid.

Now you are starting with 15 mL of 0.2 M acid solution.

mL * M = millimoles

So you have 3 millimoles of acid in solution.

Based on the chemical equation, you need 9 millimoles of base.

9 = 0.1 * mL

9/.1 = 90 mL of NaOH needed

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