Question

If 8.0 g of NH4HS(s)NH4HS(s) is placed in a sealed vessel with a volume of 1.0 L and heated to 200°C200 °C the reaction NH4HS(s)⥫⥬==NH3(g)+H2S(g)NH4HS(s) ⇌ NH3(g)+H2S(g) will occur. When the system comes to equilibrium, some NH4HS(s)NH4HS(s) is still present. Which of the following changes will lead to a reduction in the amount of NH4HS(s)NH4HS(s) that is present, assuming in all cases that equilibrium is re-established following the change? Adding more NH3(g)NH3(g) to the vessel Adding more H2S(g)H2S(g) to the vessel Adding more NH4HS(s)NH4HS(s) to the vessel Increasing the volume of the vessel Decreasing the volume of the vessel

Answer 1

Answer: The correct statements are adding more $NH_4SH(s)$ to the vessel and increasing the volume of the vessel

Explanation:

For the given chemical reaction:

$NH_4HS(s)\rightleftharpoons NH_3(g)+H_2S(g)$

According to Le-Chateliers principle, if there is any change in the variables of the reaction, the equilibrium will shift in the direction in order to minimize the effect.

The given statements are:

• Statement 1: Adding more $NH_3(g)$ to the vessel

When ammonia gas is added, the concentration of products get increased. So, by Le-Chatelier's principle, the equilibrium will shift in the direction where concentration of products must decrease, which is in the backward direction.

Thus, concentration of $NH_4HS$ will increase.

• Statement 2: Adding more $H_2S(g)$ to the vessel

When hydrogen sulfide gas is added, the concentration of products get increased. So, by Le-Chatelier's principle, the equilibrium will shift in the direction where concentration of products must decrease, which is in the backward direction.

Thus, concentration of $NH_4HS$ will increase.

• Statement 3: Adding more $NH_4HS(s)$ to the vessel

When $NH_4SH$ is added, the concentration of reactants get increased. So, by Le-Chatelier's principle, the equilibrium will shift in the direction where concentration of reactants must decrease, which is in the forward direction.

Thus, concentration of $NH_4HS$ will decrease.

• Statement 4: Increasing the volume of vessel

When volume is increased, the equilibrium will shift in the direction which produces more moles of gas.

In the given reaction, number of moles of gas is more on the product side. So, the reaction will move towards forward direction.

Thus, concentration of $NH_4HS$ will decrease.

• Statement 5: Decreasing the volume of vessel

When volume of the vessel is decreased, the equilibrium will shift in the direction which produces fewer moles of gas.

In the given reaction, number of moles of gas is less on the reactant side. So, the reaction will move towards backward direction.

Thus, concentration of $NH_4HS$ will increase.

Hence, the correct statements are adding more $NH_4SH(s)$ to the vessel and increasing the volume of the vessel