Final answer:
To dilute the HCl solution, you will need to add 240 cm³ of water.
Step-by-step explanation:
To calculate the volume of water that needs to be added to dilute the HCl solution, we can use the equation:
(stock concentration) × (stock volume) = (final concentration) × (final volume)
Let's solve for the unknown volume:
(0.600 mol/dm³) × (40.0 cm³) = (0.100 mol/dm³) × (unknown volume)
Dividing both sides by 0.100 mol/dm³, we find that the unknown volume is 240 cm³.