Question

Lab 7 questions for disturbing equilibrium

Answer 1

Based on the nature of the indicator Bromophenol blue,

• it is yellow in an acid and blue in a base.
• Adding an acid will change the blue colour to yellow.
• On addition of an acid, hydrogen ion concentration increases, equilibrium shifts towards removal of excess hydrogen ions and the solution will turn yellow.
• The solution can be made to change from yellow to blue by addition of base.
• On addition of a base, hydroxide ion concentration increases, equilibrium shifts towards removal of excess hydroxide ions and the solution will turn blue.
• equilibrium shifts towards removal of excess hydroxide ions.

What is an indicator?

An indicator is a organic dye which changes colour according to the pH of the medium it is present in.

Examples of indicators include:

• Methyl Orange
• Methyl red
• Bromophenol blue

Bromophenol blue is an acid–base indicator whose range of colour change lies between pH 3.0 and 4.6.

It changes from yellow at pH 3.0 to blue at pH 4.6.

• Bromophenol is yellow in an acid and blue in a base.
• Adding an acid will change a blue colour of bromophenol in a basic solution to yellow.
• On addition of an acid, hydrogen ion concentration increases, equilibrium shifts towards removal of excess hydrogen ions and the solution will turn yellow.
• The solution can be made to change from yellow to blue by addition of base.
• On addition of a base, hydroxide ion concentration increases, equilibrium shifts towards removal of excess hydroxide ions and the solution will turn blue.
• When hydroxide ion is added to the solution in step 3, equilibrium shifts towards removal of excess hydroxide ions.

Therefore, Bromophenol blue is a useful indicator between pH range 3.5 ⇌ 4.6.

Learn more about indicators at: brainly.com/question/1820795