Question

question 1
when the rate of vaporization and the rate of condensation are in equilibrium,...
○ there is no gas present.
○ there are equal amounts of liquid and gas.
○ the vapor pressure will be stable.
○ the liquid will boil.

Explanation:

1. Analyze "there is no gas present": When vaporization and condensation are in equilibrium, gas (vapor) is present as condensation is the change from gas to liquid and vaporization is liquid to gas. So this is incorrect.
2. Analyze "there are equal amounts of liquid and gas": Equilibrium between vaporization and condensation doesn't mean equal amounts of liquid and gas. The amounts depend on various factors, and equilibrium is about rates, not amounts. So this is incorrect.
3. Analyze "the vapor pressure will be stable": Vapor pressure is the pressure exerted by vapor in equilibrium with its liquid. When the rate of vaporization (liquid to gas) equals the rate of condensation (gas to liquid), the amount of vapor (and thus its pressure) remains constant. So vapor pressure is stable. This is correct.
4. Analyze "the liquid will boil": Boiling occurs when vapor pressure equals atmospheric pressure, not when vaporization and condensation rates are equal (which is the condition for equilibrium vapor pressure at a given temperature, not boiling). So this is incorrect.

Answer:

the vapor pressure will be stable.