| Property | Water | Organic Solvents (General) |
|---|---|---|
| Polarity | Very high (dielectric constant ≈ 80) | Varies widely: very polar (DMF, DMSO ≈ 37–47), medium (acetone ≈ 21), low/non-polar (hexane ≈ 2) |
| Solubility of ionic compounds | Excellent (salts, acids, bases) | Poor to negligible (except a few like alcohols, acetonitrile) |
| Solubility of non-polar organics | Poor (“like dissolves like” rule) | Excellent for hydrocarbons, oils, fats, most organic molecules |
| Boiling point | High (100 °C) | Usually low to moderate (30–150 °C); easier to evaporate |
| Freezing point | 0 °C (can freeze in cold labs) | Usually much lower (e.g., acetone –95 °C, ether –116 °C) |
| Toxicity | Non-toxic, safe for biological use | Varies: some highly toxic (CHCl₃, CCl₄), carcinogenic (benzene), or relatively safe (ethanol, ethyl acetate) |
| Flammability | Non-flammable | Most are highly flammable (exceptions: CH₂Cl₂, CHCl₃) |
| Environmental impact | Green, biodegradable, no VOC issues | Many are VOCs, hazardous waste, require special disposal |
| Cost & availability | Extremely cheap and abundant | Generally more expensive; some restricted or controlled |
| Reactivity | Reacts with Grignard reagents, alkali metals, acid chlorides, etc. | Mostly inert toward organometallics and highly reactive compounds |
| Ease of drying/removal | Difficult to make completely anhydrous; forms azeotropes | Many can be dried easily (molecular sieves, distillation) and removed by rotary evaporation |
| Heat capacity | Very high (good temperature buffer) | Low to moderate (faster heating/cooling) |
| Typical applications | Biological systems, inorganic chemistry, aqueous extractions, green chemistry | Organic synthesis, extractions of organics, recrystallization, chromatography, paint/industry |
| Waste disposal | Usually can be disposed down the drain (if uncontaminated) | Requires hazardous waste collection and treatment |
Related Topics
Advantages of Water as Solvent
Disadvantages of Water as Solvent