i need help in writing chemical equations?

Question

Write balanced chemical equations or formulas (annotated where appropriate) for each of the following descriptions:

(i) oxygen undergoes photodissociation in the upper atmosphere;

(ii) the nitric oxide molecule undergoes photoionisation in the upper atmosphere;

(iii) ozone is formed in the upper atmosphere;

(iv) ozone is destroyed in the upper atmosphere;

(v) nitric oxide catalyses the decomposition of ozone in the stratosphere;

(vi) nitrogen dioxide is an acidic oxide and forms an acid solution in water;

(vii) sulfur dioxide emissions from industrial sources cause acid rain;

(viii) why rainwater is naturally acidic, even in the absence of any polluting gases

(ix) despite the answer in (viii), why the pH of unpolluted sea water is about 8.2

(x) why nitrogen is not, but carbon dioxide is, a 'greenhouse gas'

Answer 1

I'm not that great on the upper atmosphere.
So...
6. NO2 reacts with water 2NO2+H2O= HNO3+HNO2.
7. SO2+H2O = H2SO3, a weak acid.
8. Atmospheric CO2 dissolves in water to form "carbonic acid". At saturation, the pH of water drops to 5.6.
9. There is sufficient Mg and Ca ions in seawater to react with H2CO3 to form the bicarbonate and carbonate.
10. N2 does not absorb in the infrared.