Answer to Question #173993 in Organic Chemistry for gregr

Question

Hydrogen gas (colorless) reacts with pure iodine vapor (purple) to give hydrogen iodide gas (colorless).

Write a balanced equation for this reaction: H2 (g)+ I2 (g) → 2HI (g)

1. If the equilibrium mixture of these three gases is light purple in color, what change in color would you expect to observe if more hydrogen gas were added to the system? EXPLAIN WHY IT IS DARKER PURPLE

1. If the equilibrium mixture of these three gases is light purple in color, what change in color would you expect to observe if some of the hydrogen iodide gas were removed from the system? EXPLAIN WHY DARKER PURPLE

1. Consider the following equilibrium: Heat + CaCO3 (s)  CaO (s) + CO2 (g)

1. If the pressure of CO2 (g) increases, in which direction will the equilibrium shift? EXPLAIN WHY SHIFTS RIGHT

1. If the temperature is increased, in which direction will the equilibrium shift? Justify. EXPLAIN WHY SHIFT RIGHT

1. If the temperature is decreased, in which direction will the equilibrium shift? Justify. EXPLAIN WHY SHIFT LEFT

Answer 1

The given reaction is

$H_2(g) +I_2(g) \rightleftharpoons 2HI(g)$

The change in concentration of reactant or product is govern by Le chatlier's principle

1. If hydrogen gas is added to reactant side equilibrium is shift in forward direction and thus purple colour changes to colourless due to formation of more HI.
2. If HI is removed from system then reaction will move toward forward and thus it become colourless.

Now consider the second reaction as follows

$CaCO_3 (s)+ Heat \rightleftharpoons CaO(s)+ CO_2)(g)$

1. As the number of mole of gases in product side is more so on increasing the pressure of CO₂ it will shift reaction toward backward direction and thus more reactant will form as per Le chatlier's principle.
2. As we know that reaction is endothermic reaction so on increasing the temperature equilibrium will shift toward forward direction .
3. And on decreasing the temperature equilibrium will shift toward backward direction and thus more reactant will form.