Solubility Curves: Solubility of Salts vs Temperature
Interactive solubility curves for nine common salts in water (g of solute per 100 g of H₂O, 0 to 100 °C). Click or tap anywhere on a curve to read the solubility at that temperature. Points below a curve are unsaturated, on the curve saturated, and above it supersaturated.
| Substance | Formula | 0 °C | 10 °C | 20 °C | 30 °C | 40 °C | 50 °C | 60 °C | 70 °C | 80 °C | 90 °C | 100 °C |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Ammonium chloride | NH4Cl | 29.4 | 33.2 | 37.2 | 41.4 | 45.8 | 50.4 | 55.3 | 60.2 | 65.6 | 71.2 | 77.3 |
| Potassium bromide | KBr | 53.6 | 59.5 | 65.3 | 70.7 | 75.4 | — | 85.5 | — | 94.9 | 99.2 | 104 |
| Potassium chlorate | KClO3 | 3.3 | 5.2 | 7.3 | 10.1 | 13.9 | — | 23.8 | — | 37.5 | 46 | 56.3 |
| Potassium chloride | KCl | 28 | 31.2 | 34.2 | 37.2 | 40.1 | 42.6 | 45.8 | — | 51.3 | 53.9 | 56.3 |
| Potassium iodide | KI | 128 | 136 | 144 | 153 | 162 | — | 176 | — | 192 | 198 | 206 |
| Potassium nitrate | KNO3 | 13.3 | 20.9 | 31.6 | 45.8 | 63.9 | 85.5 | 110 | 138 | 169 | 202 | 246 |
| Sodium chloride | NaCl | 35.65 | 35.72 | 35.89 | 36.09 | 36.37 | 36.69 | 37.04 | 37.46 | 37.93 | 38.47 | 38.99 |
| Sodium nitrate | NaNO3 | 73 | 80.8 | 87.6 | 94.9 | 102 | — | 122 | — | 148 | — | 180 |
| Sodium sulfate | Na2SO4 | 4.9 | 9.1 | 19.5 | 40.8 | 48.8 | — | 45.3 | — | 43.7 | 42.7 | 42.5 |
Important Notes
- Values are grams of solute that saturate 100 g of water at each temperature. A dash means the compilation has no measurement at that temperature — the curve interpolates between neighbors.
- Most ionic solids dissolve more at higher temperature (steeply for KNO₃, barely for NaCl). Sodium sulfate is the classic exception: its solubility peaks between 30 and 40 °C (the Na₂SO₄·10H₂O to Na₂SO₄ transition at 32.4 °C) and then falls — retrograde solubility.
- Reading the chart: a point below a curve is an unsaturated solution, on the curve saturated, above it supersaturated (crystallization is the usual result of cooling a saturated solution).
- Crossing curves explain fractional crystallization: cooling a hot mixed solution precipitates the salt whose curve falls fastest (e.g. KNO₃) while the flat-curve salt (NaCl) stays dissolved.
- ChemWhiz problems that need a solubility supply the value in the problem statement; this chart is the general reference.
Source: Wikipedia, Solubility table (aqueous solubility data, largely from the CRC Handbook of Chemistry and Physics) (CC BY-SA 4.0)