A poorly ventilated indoor gas heater burns butane fuel. Under these conditions, a dangerous accumulation of carbon monoxide, rather than carbon dioxide, can occur. Explain, in terms of combustion conditions, why carbon monoxide is produced instead of carbon dioxide.

A power plant pre-treats its coal supply to wash out sulfur compounds before combustion. Explain how this pre-combustion treatment helps to protect nearby medieval cathedrals constructed from limestone (calcium carbonate, ${CaCO}_3$) from accelerated structural deterioration.

Heavy-duty diesel trucks release significant amounts of nitrogen oxides (${NO}_x$) from their exhaust systems, despite nitrogen gas possessing a very strong triple bond that makes it highly unreactive under normal conditions. Explain why nitrogen oxides are able to form inside the cylinders of these diesel engines.