**Problem : **

Calculate the volume of a 0.753 *M* sodium hydroxide solution that is
neutralized by the
addition of 100 mL of a 1.203 *M* sulfuric acid solution.

This problem requires you to perform the following unit cancellation calculation:

**Problem : **

If the volume of a 100 L solution of 1.1 moles of hydrogen in 6.0 moles argon is suddenly doubled, what happens to the mole fraction of hydrogen in that solution?

The mole fraction of a solute does not depend on the volume of the solution. Mole fraction only depends on the molar amount of each component. Because we did not add or subtract any hydrogen or argon, the mole fraction of hydrogen remains unchanged.

**Problem : **

What is the concentration of HCl stock solution that can create 250 mL of a
1.0 *M* solution
that is prepared by the dilution of 50 mL of the HCl stock solution?

By rearranging the expression c_{1} v_{1} = c_{2}
v_{2}
to solve for c_{1}, we find the concentration of the HCl stock
solution: