The ultimate analysis of a coal$-$fired boiler showed $57\mathrm{.}04\%$ total C$,30\mathrm{.}5\%VCM,1\mathrm{.}2\%N,9\mathrm{.}7\%$ ash and $6\mathrm{.}3\%S.$ Analysis

of the wetted refuse showed $13\mathrm{.}8\%$ Fixed Carbon, $21\mathrm{.}5\%$ VCM$,47\mathrm{.}8\%$ ash and $15\mathrm{.}9\%$ water. Air is at $28$ degrees C$,756$

$mmHg$ with $76\%$ relative humidity. The Ultimate analysis of coal contains: $57\mathrm{.}04\%C,4\mathrm{.}68\%H,21\mathrm{.}08\%O,1\mathrm{.}2\%N,9\mathrm{.}7\%$

ash and $6\mathrm{.}3\%$ S$.$ Calculate the:

a$.\%$ excess $O_2$ used in the combustion.

b$.\%S{O}_2$ in the stack gas.