When the positive ion of one compound replaces the positive ion of another compound?

clouds form

solid ice forms on leaves.

water droplets form on grass.

because of all the things that happen around the us, many people get into arguments which sadly could get physical, but we should actually make a change for that.

colorless gas, exhibiting a blue glow when placed in an electric field

b) solid

its a type of rock

the answer is 0.42 is that is an option. this question provides no info