Molarity of Unknown and sodium hydroxide.

  • #1
imaciel
2
0
This is the question:

Your friend gives you an unlabeled bottle that contains either hydrochloric, sulfuric or phosphoric acid. The concentration of the unknown acid is 0.2128 M. A titration of 21.00 mL of the acid with a 0.2723 M sodium hydroxide solution required 32.83 mL of sodium hydroxide. Which of the three acids is in the bottle?

A. sulfuric acid
B. hydrochloric acid
C. phosphoric acid

Steps:
I solved for the molar mass of 3 choices, but I don't know how to get the molar mass from the problem. I can get # of moles in the solution but what about gram?

molar mass= gram/moles...

tnx
 
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  • #2
Your titration will tell you how many moles of H+ are present. The result should be an integer multiple of 0.2128.

Enough of a hint?
 
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