Answer to Question #171269 in General Chemistry for dsaf

Question

1. Dinitrogen tetroxide (a colorless gas) is converted to nitrogen dioxide (a dark reddish-brown gas) and is endothermic in the forward direction.
2. -Write a balanced equation for this reaction.
3. If a closed container with a mixture of these two gases at equilibrium is a light brown in color when it is at room temperature (25°C), what change in color would you expect to observe if the container is placed in boiling water? Justify.
4. If a closed container with a mixture of these two gases at equilibrium is a light brown in color when it is at room temperature (25°C), what change in color would you expect to observe if the container is placed in ice water? Justify.

Answer 1

Q171269

1. Dinitrogen tetroxide (a colorless gas) is converted to nitrogen dioxide (a dark reddish-brown gas) and is endothermic in the forward direction.
2. -Write a balanced equation for this reaction.
3. If a closed container with a mixture of these two gases at equilibrium is a light brown in color when it is at room temperature (25°C), what change in color would you expect to observe if the container is placed in boiling water? Justify.
4. If a closed container with a mixture of these two gases at equilibrium is a light brown in color when it is at room temperature (25°C), what change in color would you expect to observe if the container is placed in ice water? Justify.

Solution:

Dinitrogen tetroxide (a colorless gas) is converted to nitrogen dioxide (a dark reddish-brown gas) and is endothermic in the forward direction.

Write a balanced equation for this reaction.

Dinitrogen tetroxide (N₂O₄) is colorless gas and nitrogen dioxide (NO₂) is dark reddish brown color gas.

We are told in the question that the forward reaction is endothermic, which means for converting N2O4 to NO2 we must supply heat.

N₂O₄ + Heat <===> 2NO₂(g)

colorless Reddish brown color

The forward reaction is endothermic here. If we supply heat then the reaction will move to

forward direction

The reverse reaction will be exothermic . If we remove heat then the reaction will move in backward direction.

If a closed container with a mixture of these two gases at equilibrium is a light brown in color when it is at room temperature (25°C), what change in color would you expect to observe if the container is placed in boiling water? Justify.

If the container containing given mixture is put in the hot water bath then the color of the mixture will change to more dark brown or it may turn to reddish brown color, this is because N₂O₄ will convert to NO₂. The concentration of N₂O₄ will decrease and the concentration of NO₂ will increase. NO2 is reddish brown in color, so the color of the solution will turn more darker.

If a closed container with a mixture of these two gases at equilibrium is a light brown in color when it is at room temperature (25°C), what change in color would you expect to observe if the container is placed in ice water? Justify.

In next case if the mixture is placed in the ice bath, then the color of the mixture will fade away.

This is because now the heat is removed from the mixture.

The backward reaction is exothermic. Removal of heat by cooling the mixture will favor the backward reaction. Some of the NO₂ will convert to N₂O₄.

The concentration of NO₂ will decrease and concentration of N₂O₄. will increase.

As we know that N₂O₄. is colorless, so the color of mixture will become light brown or even it may fade away.

Thank you. :)