Question

Calculate the amount of 1 M NaOH aqueous solution needed to make 100 mL of 0.5 M NaOH aqueous solution.

Answer 1

You need 50 mL of 1 mol/L NaOH.

See How do you do dilution calculations?

`c_1V_1 = c_2V_2`

`c_1` = 1 mol/L; `V_1` = ?
`c_2` = 0.5 mol/L; `V_2` = 0.100 L

`V_1 = V_2 × c_2/c_1` = `"0.100 L" × "0.5 mol/L"/"1 mol/L"` = 0.05 L = 50 mL

You need 50 mL of 1 mol/L NaOH to make 100 mL of 0.5 mol/L NaOH.