You can smell perfume because of which change of state

The state changes from liquid to gaseous state.

Explanation:

Perfume is a mixture of aroma oils which are mixed with water or ethanol solvent. It is present in liquid state in the perfume bottle.

When the perfume is sprayed, it produces tiny droplets of water that are easily suspended in air. The tiny droplets when come in contact with the air, it easily gets evaporated and hence gets converted into gaseous state. Thew particles of gaseous state have high kinetic energy with them and therefore we can easily smell it.

Thus, the state changes from liquid to gaseous state.

clouds form

solid ice forms on leaves.

water droplets form on grass.

if you mean hydrogen and oxygen then water is the product