Question

Predict whether the equilibria

I) CO2(g) + 2 NH3(g) =
CO(NH2)2(s) + H2O(g),
AH° = -90 kJ
II) Ni(s) + 4 CO(g) = Ni(CO)4(8),
AH° = -161 kJ
will shift toward products or reactants with a
temperature increase.
1. I shifts toward reactants and II shifts
toward products.
2. Both I and II shift toward products.
3. Unable to determine
4. Both I and II shift toward reactants.
5. I shifts toward products and II shifts to-
ward reactants.

Answer 1

The correct answer is option 4.

Step-by-step explanation:

Any change in the equilibrium is studied on the basis of Le-Chatelier's principle.

This principle states that if there is any change in the variables of the reaction, the equilibrium will shift in the direction to minimize the effect.

For exothermic reaction :ΔH = negative

• If the temperature is increased, so according to the Le-Chatlier's principle , the equilibrium will shift in the direction where decrease in temperature occurs.So, equilibrium will move in backward direction.
• If the temperature is decreased , so according to the Le-Chatlier's principle , the equilibrium will shift in the direction where increase in temperature occurs.So, equilibrium will move in forward direction.

For the given equation:

I)
`CO_2(g) + 2 NH_3(g) \leftrightharpoons CO(NH_2)_2(s) + H_2O(g)` ,ΔH° = -90 kJ

On Increasing the temperature

This is an exothermic reaction, backward reaction will decrease the temperature. Hence, the equilibrium will shift in the left direction that is towards reactants.

II)
`Ni(s) + 4 CO(g)\leftrightharpoons Ni(CO)4(g)` ,ΔH° = -161 kJ

On Increasing the temperature

This is an exothermic reaction, backward reaction will decrease the temperature. Hence, the equilibrium will shift in the left direction that is towards reactants.