Intermediate · 2 min
Diluting a solution
Adding solvent lowers a solution's concentration while leaving the amount of solute unchanged, provided none is lost or reacts. The initial concentration multiplied by initial volume equals the final concentration multiplied by final volume. Diluting 100 millilitres of a 2-molar solution to a final volume of 400 millilitres gives 0.5 molar. The final volume is four times larger, so the concentration is four times smaller. This is a calculation exercise, not an instruction to handle chemicals.
Visual explanation
Diluting a solution
- The same amount of dissolved solute
- Solvent is added; solution volume increases
- Concentration decreases
This assumes no solute is added, removed, or consumed by a reaction. Mixing alone does not change the amount of solute.
Simplified diagram. Read the explanation for the conditions and limits.
Interactive experiment
Dilution lab
Start with 100 mL at 2 mol/L. Change the final volume and watch the concentration.
Concentration
2 mol/L
c = (2 × 100) / 100 = 2 mol/L
Model: the amount of solute stays fixed, with no loss or reaction. The dots represent the same amount at every volume.