Question

In the laboratory, hydrogen chloride (HCl(g)) and ammonia (NH₃(g)) often escape from bottles of their solutions and react to form ammonium chloride (NH₄Cl(s)), the white glaze often seen on glassware. Assuming that the number of moles of each gas that escapes into the room is the same, what is the maximum partial pressure of HCl and NH₃ in the laboratory at room temperature? (Hint: The partial pressures will be equal and are at their maximum value when at equilibrium.)

a) 0.5 atm each
b) Depends on the volume of the room
c) Non-zero constant value
d) Cannot be determined

Answer 1

The maximum partial pressures of HCl(g) and NH₃(g) in the laboratory at room temperature, when equilibrium is reached, cannot be determined without additional information such as the volume of the room or initial concentrations.

Step-by-step explanation:

In the reaction where hydrogen chloride (HCl(g)) and ammonia (NH₃(g)) escape and form ammonium chloride (NH₄Cl(s)), the maximum partial pressures of HCl and NH₃ will be equal due to the stoichiometry of the reaction, which is a 1:1 molar ratio. At equilibrium, the reaction is represented by NH₃(g) + HCl(g) ⇌ NH₄Cl(s). If an equal number of moles of HCl(g) and NH₃(g) escape into the room and reach equilibrium, the partial pressures of these gases will be the same as the reaction quotient will be equal to the equilibrium constant (Q = K).

Given that equilibrium is established and the partial pressure of each gas is at its maximum value when the reaction has reached this state, the specific numeric value of the partial pressures cannot be determined without additional information, such as the room's volume or the initial concentrations. Thus, without additional data, the maximum partial pressures of HCl and NH₃ at equilibrium cannot be specified from the options provided. Therefore, the correct answer is cannot be determined (d).