Question

I need help with these questions.

Part I.A 1. Why did the indicator initially turn blue when NaOH was added to flask A? Consider equilibrium: Hin + H2O + H2O + In [1 mark] 2. When you left the flask A to stand for several minutes after the addition of NaOH, why did the contents of the flask A slowly change colour back from blue to yellow? Consider equilibriums: Hin + H2O + H30+ + In [2 marks] CO2(g) + H2O + H2CO3 + H30* + HCO3- 3. The time delay for the second colour change back to yellow implies that the overall speed of the two-step conversion of carbon dioxide is slow. Which is the slow step? [1 mark] Part I. B 4. How soon after addition of the HCl to Na2CO: did gas formation occur? What is the numerical value of the equilibrium constant for that reaction? [1 mark] H2CO3 - CO2(g) + H20; K=

Answer 1

1. The addition of NaOH makes the solution basic. this drives the Indicator equilibrium reaction in the forward direction, producing more of in- which is blue in color thereby changing the color of the solution