Understanding Dilution
Quick Answer: Dilution is the process of reducing the concentration of a solute in a solution by adding more solvent. The number of moles of solute remains unchanged: M1V1 = M2V2.
Key Formula & Variables
M1V1 = M2V2 where M1 is initial molarity, V1 is initial volume, M2 is final molarity, and V2 is final volume. Volumes must use the same unit (both mL or both L). This equation is fundamental in volumetric analysis and titration experiments.
Solved Examples
M1 = 2.0 M, V1 = 50 mL
V2 = 200 mL
M2 = (2.0 × 50)/200
M2 = 0.50 M
Stock: 6.0 M HCl, Need: 200 mL of 1.5 M
V1 = (1.5 × 200)/6.0
V1 = 50 mL
10 mL of 1 M → 100 mL (0.1 M)
10 mL of 0.1 M → 100 mL
Final = 0.01 M
FAQs
The equation works with any volume unit (mL, L, etc.) as long as V1 and V2 use the same unit, because the units cancel out in the ratio.
A stock solution is a concentrated solution of known molarity that is stored and used to prepare working solutions of lower concentration via dilution.
No. Adding solvent only increases volume and decreases concentration. The total moles of solute (n = M × V) remain strictly constant.
The dilution factor (DF) is the ratio of final volume to initial volume: DF = V2/V1. It tells you how many times the original solution has been diluted.