Answer:
1) Tin. It is stable to water under ambient conditions but on heating with steam, tin reacts with water to from tin dioxide and hydrogen. It is stable in air under ambient conditions but on heating in air or oxygen, tin reacts with oxygen to from tin dioxide.
2) Nitric oxide combines with water vapour in the atmosphere to form nitric acid, which is one of the components of acid rain. Heightened levels of atmospheric nitric oxide resulting from industrial activity were also one of the causes of gradual depletion of the ozone layer in the upper atmosphere.