Universal Indicator is a pH indicator that has different colors to indicate the range of the pH of the solution it is in. This is opposed to indicators like phenolphthalein which have only two different colors and are able to indicate only whether the pH is above or below a certain point. It usually has the following composition:

• Methanol
• Propan-1-ol
• Phenolphthalein, sodium salt
• Methyl red, sodium salt
• Water
• Phenol,4,4'-(3h-2,1-benzoxathiol-3-ylidene)bis2-bromo--methy l-6-(1-methylethyl)-, s,s-dioxide, monosodium salt
• Phenol,4,4'-(3h-2,1-benzoxathiol-3-ylidene)bis5-methyl2-(1-m ethylethyl)-, s,s-dioxide, monosodium salt

Universal indicator is a flammable liquid. It may cause respiratory tract irritation. Prolonged or repeated contact may cause dry, cracked skin, irritation or kidney damage. It may also form explosive peroxides.

Colors and meanings

• Very acidic - Red
• Acidic - Orange/Yellow
• Neutral - Green
• Basic/base/alkali - Blue
• Very basic/base/alkali - Purple

More details

• Physical state: Liquid
• Appearance: light green in water solvent; dark green alone
• Odour: alcohol-like
• pH value: Approximately 7.5
• Vapour pressure: 25 mmHg (3.3 kPa)
• Vapour Density: 1.3 kg/m³
• Evaporation rate: Not available
• Viscosity: Not available
• Boiling point: 80 °C
• Freezing/melting point: Not available.
• Decomposition temperature: Not available.
• Solubility: Soluble in water.
• Specific gravity/Density: 0.93 g/cm³
• Molecular formula: Mixture
• Molecular weight: Not available

pH indicators