- Acids have the following physical properties:
- Tastes sour
- Turns moist blue litmus to red
- pH value < 7
- Can conduct electricity
Colour of Litmus in Acids
- Litmus can be used as acid/alkali indicator.
- Image below shows the colour of litmus paper when immerse in acid and alkali.
- The litmus turn red in acids and turn blue in alkali.
pH value of acids
- pH value is quantity to measure the concentration of hydrogen ions in a solution. The higher the concentration of hydrogen, the lower the pH value of the solution.
- Pure water has pH value of 7.
- All acids has pH value lower than 7.
Electrical Conductivity of Acids
- Acids are covalent compounds.
- However, when acids dissolve in water, they ionise to form ions in the solution.
- Since there are free moving ions in the solution, hence the solution can act as an electrolyte to conduct electricity.