A chemical engineer investigating the conversion rate in the reaction of ethyl acetate with

sodium hydroxide is conducting analysis through back titration. The solution used in titration

is $0\mathrm{.}05M$ caustic soda $($sodium hydroxide$).$ The concentrations of ethyl acetate and caustic

soda involved in the reaction are both $0\mathrm{.}1$ moles. In the sample containers, there is a

phenolphthalein indicator and $20mL$ of $0\mathrm{.}1M$ hydrochloric acid.

At two$-$minute intervals from the start of the reaction, $20mL$ samples were taken from the

reaction vessel and added to the sample containers. The prepared samples were titrated

with sodium hydroxide. The values read from the burette after titration are indicated in the

table below.

a$)$ Determine a limiting component for this experiment and find the variation of the

conversion rate over time.

b$)$ Suggest the residence time required in the reactor for a $70\%$ conversion.