Lab 3

Question 1

What is the purpose of the third experiment?

Answer 1

prepare acidic solution, basic solution, and several buffered solution containing the same indicator bromocresol green is prepared and each solution’s absorbance measured. Concentration of INDICATOR and equilibrium constant Ka for dissociation of indicator is determined

Question 2

What type of indicator is bromocresol green?

Answer 2

weak acid

Question 3

When does the indicator change colour?

Answer 3

added to a colourless basic solution in the In- form

Question 4

What is the equation that represents a weak acid indicator?

Answer 4

HIn + H2O –> H3O+ + In-

Question 5

What is the colour of a buffered solution when indicator is added?

Answer 5

colour combination of the HIn and In- form

Question 6

What happens when the indicator is added to a colourless acidic solution?

Answer 6

indicator will all be in HIn form and solution will be the colour of HIn