27. Which event will most likely occur in rising air?
A. clearing skies
B. cloud formation
C. decreasing relative humidity
D. increasing temperature

B. cloud formation

Explanation:

The event that will most likely occur is cloud formation. This is because Rising Air is the key process in the production of clouds and precipitation. This occurs because the air rises and as it rises it begins to expand, it expands so much so that the temperature of the air begins to decrease and humidity rises  until  cloud droplets begin forming as the excess water vapor condenses on the the air particles.

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.