Question

What is the molarity of a nitric acid solution if 43.31 mL 0.3000 M KOH solution is needed to neutralize 20.00 mL of the acid solution?

Answer 1

Answer:

First you need a balanced equation of the neutralization reaction:

HNO3 (nitric acid) + KOH --> KNO3 + H2O

Now then, there's a fairly simple equation you can use for problems like this:

a x [A] x Va = b x [B] x Vb

In this equation, a is the number of hydrogen ions that the acid can donate.  For HNO3 that number is 1.  [A] is the molar concentration of the acid (which is what you're trying to calculate), and Va is the volume of the acid, 20.00 mL.  On the other side of the equation, b is the number of hydrogen ions the base can accept (or the number of hydroxide ions the base has).  For KOH that number is 1.  [B] is the molar concentration of the base (0.1000 M) and Vb is the volume of the base (43.33 mL).

1 x [A] x 20.00 mL = 1 x 0.1000 M x 43.33 mL

[A] x 20.00 mL = 4.333 M*mL

[A] = 0.2167 M