Biological degradation of Mucilage is given below $($where M is Mucilage$)$

$M+O_{2}C{O}_2+N{H}_3$

a$.$ Write a rate equation for the disappearance of Mucilage assuming that the rate is elementer $($follows the stoichiometry$).$ State the order of the reaction.

b$.$ Assume $O_2$ is constant in water, derive a relationship for the disappearance of Mucilage with time in a batch reactor. State the order of the reaction.

c$.$ When $O_2$ is constant in water, $1000m\frac{g}{L}$ of $M$ is reduced into $500m\frac{g}{L}$ of $M$ in $1$ hour in a batch reactor. How long it takes to remove $90\%$ of M$.$