Jun 16, 2015
6
0
Status
Pre-Dental
Hello, #44 on the 2009 DAT reads "If 50mL of H2SO4 required 50 mL of 1.0M NaOH for a complete neutralization reaction, according to the equation shown below, what would be the molarity of the acid?
2NaOH + H2SO4—> Na2SO4 +2H2O " the correct answer is B 0.5

I understand how to use the normalcy equation n1M1V1+n2M2V2 , but why do I not have to take into account the coefficients in the equation???
 
Jun 16, 2015
6
0
Status
Pre-Dental
I set up the equation
n1M1V1=n2M2V2
(1)(1.0M)(.05L)=(2)(M2)(.05L)
where M2=molarity of the acid=0.5

I just don't get why I do not have to consider the equation coefficients where there is a 2 in front of the OH— thank you!
 

Meeza

5+ Year Member
Jul 25, 2014
249
190
Status
Dental Student
It's simply a balanced equation, representing the ratio of each reactant and product, and therefore wouldn't affect your calculation. Since molarity was already provided, it isn't necessary to calculate it (molarity is just moles/L). :)
 
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May 9, 2014
196
73
Toronto, Ontario
Status
Pre-Dental
in this case its easier to approach it through logic and realize that both solutions have the same volume.
Since moles and volume are equal across both solutions, yet one is a diprotic acid, it must have half the concentration as the base
 
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