Question

Question #ec0eb

Answer 1

This is a very simple dilution problem, all you have to do is apply the formula

`C_1V_1 = C_2V_2`

You start with `"5.0 mL"` of a `"3.0 M NaOH"` solution; these values will be `V_1` and `C_1`. `V_2` will be the final volume of the solution, which in your case is `"50.0 mL"`. Therefore,

`C_1V_1 = C_2V_2 => C_2 = C_1 * V_1/V_2`

`C_2 = "3.0 M" * ("5.0 mL")/("50.0 mL") = "0.3 M"`

This is the same is diluting the solution by a factor of 10. The volume is ten times bigger, so the concentration must be ten times smaller.

If, for instance, you were asked to determine the molarity for a final volume of `"1.0 mL"`, you would have had

`C_2 = C_1 * V_1/V_2 = 3.0 * 5.0/1.0 = "15 M"`

The final volume is five times smaller, so the concetration must be five times greater.