Balance the Chemical reaction
2CH4—C2H6+3H2O

2CH4 - - - > C2H6+3H2O

2C2

8H12

0O3

6CH4 + 3O - - - > 3C2H6+3H2O

6C6

24H24

3O3

I added oxygen to the reactant side because I presumed this must be a combustion of methane; since, H2O is made in the product side.

Hope this helps!

acid rain does not usually kill trees directly. instead, it is more likely to weaken the trees by damaging their leaves, limiting the nutrients available to them, or poisoning them with toxic substances slowly released from the soil. the main atmospheric pollutants that affect trees are nitrates and sulphates.