To determine what would happen if a small amount of nitrous acid (HNO2) is added to the system at equilibrium, we need to analyze the reaction and the effect of adding HNO2.
The given reaction is:
HN3(§¤) + 2 H2O(§¤) + heat ➞ N2H4(§¤) + HNO2(§¤)
At equilibrium, the forward and reverse reactions occur at equal rates. This means that the concentrations of all the species involved in the reaction remain constant over time.
When a small amount of HNO2 is added, it will react with hydrazoic acid (HN3) and shift the equilibrium position of the reaction. However, to determine the direction of the shift, we need to consider the reaction stoichiometry and Le Chatelier's principle.
According to the given reaction, the formation of HNO2 requires the consumption of hydrazoic acid. Therefore, by adding more HNO2, it will cause the reaction to shift towards the left, resulting in a decrease in the concentration of HN3 and an increase in the concentration of HNO2.
As a result, the system will no longer be at equilibrium, and the concentrations of the species involved in the reaction will start to change. The amount of hydrazoic acid (HN3) will decrease, while the amount of nitrous acid (HNO2) will increase.
It is important to note that the heat term in the reaction indicates that the reaction is exothermic. Therefore, the increase in HNO2 will also be accompanied by an increase in temperature due to the release of heat.
Overall, by adding a small amount of nitrous acid (HNO2), the equilibrium position of the reaction will shift towards the left, resulting in a decrease in hydrazoic acid (HN3), an increase in nitrous acid (HNO2), and an increase in temperature.