what were happen to relative humidity of air if it were to rise in the troposphere ?

Answer 1

All else being equal, the relative humidity would rise. When air is forced to rise, such as by being blown over a mountain range, this results in the humidity rising until clouds form, and rain falls on the upwind side of the mountain. When the air crosses the mountain and goes down the other side, it is drier (and warmer!)

Answer 2

In general as you rise in the troposphere the temperature falls. As the temperature falls, the relativite humidity increases reaching 100% when the temperature falls to the dewpoint.