When sulphur dioxide is dissolved in water and a drop of Universal Indicator was added the indicator, what colour would the indicator turn ?
Yellow, orange, or red depending upon the concentration of the acid formed.
To determine the color that the Universal Indicator would turn when sulphur dioxide is dissolved in water, we need to understand the behavior of both substances.
Sulphur dioxide (SO2) is a gas that can dissolve in water, forming sulfurous acid (H2SO3). Sulfurous acid is a weak acid that can release protons, resulting in an increase in hydrogen ion concentration (H+) in the solution.
Universal Indicator is a mixture of several different indicators that are sensitive to changes in pH. Each indicator in the mixture has a different color at different pH levels. When Universal Indicator is added to a solution, it goes through a range of colors to represent the pH of the solution.
In the case of dissolving sulphur dioxide in water, we can expect the color of the Universal Indicator to indicate the change in pH caused by the formation of sulfurous acid. Sulfurous acid is acidic, so it will increase the concentration of hydrogen ions (H+) in the solution, making it more acidic.
The Universal Indicator typically changes colors as follows:
- Red: Indicates a strongly acidic solution
- Orange: Indicates a moderately acidic solution
- Yellow: Indicates a weakly acidic solution
- Green: Indicates a neutral solution
- Blue: Indicates a weakly alkaline solution
- Violet: Indicates a moderately alkaline solution
- Reddish-purple: Indicates a strongly alkaline solution
So, when sulphur dioxide is dissolved in water, and a drop of Universal Indicator is added, the indicator is likely to turn towards the red or orange color, reflecting the increased acidity of the solution due to the formation of sulfurous acid.