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posted by  Chem Dumb on 11/26/2007 4:38:49 PM  |  status: Closed  

Titration

Course Textbook Chapter Problem
General Chemistry Chemistry: The Central Science (10th) by Brown, Lemay, Bursten 5 N/A
Question Details:
A 31.5 mL aliquot of HNO3(aq) of unknown concentration was titrated with 0.0134 M NaOH (aq).  It took 23.9 mL of the base to reach the endpoint of the titration.  What was the concentration of the (M) acid?
 
A) 1.02
 
B) 0.0102
 
C) 0.0204
 
D) 0.0051
 
E) 0.227
 
Please answer and explain the formula for this problem.
 
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posted by bookworm2 on 11/26/2007 4:51:34 PM  |  status: Live
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Response Details:
The balanced chemical reaction will be
 
NaOH + HNO3 ------> H2O + NaNO3
The acid and the base react in a 1:1 molar ratio.
 
The moles of base needed to react :
C=n/v
n=C*v
n=0.0134 mol/L * 0.0239L
n =3.20 x 10-4 moles of base
 
moles of base = moles of acid
moles of acid = 3.20 x 10-4 moles
v = 31.5mL = 0.0315L
C=n/v
C=3.20 x 10-4 moles /0.0315L
C= 0.0102M
Answer is B
 
 
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