A 25 mL sample of 0.100 M HNO3 completely reacts with NaOH according to this equation:

HNO3 (aq) + NaOH (aq) → NaNO3 (aq) + H2O (1)

How many moles of HNO3 are in the sample?

2.5x10^-3 mole.

Explanation:

Data obtained from the question include:

Volume of solution = 25mL

Molarity of HNO3 = 0.1M

Mole of HNO3 = ... ?

First, we'll begin by converting 25mL to L. This can be achieved by doing the following:

1000mL = 1L

Therefore, 25mL = 25/1000 = 0.025L

Now, we can obtain the number of mole of HNO3 present in the solution as follow:

Molarity = mole / Volume

Mole = Molarity x Volume

Mole = 0.1 x 0.025

Mole = 2.5x10^-3 mole.

Therefore, 2.5x10^-3 mole of HNO3 is present in the solution.