For an elementary reaction in a well$-$stirred batch reactor, concentration$-$time data are obtained. use the Least squares method for this reaction. Time, t $[$min$]50100200300$ CA$($t$)[$M$]0\mathrm{.}007870\mathrm{.}006490\mathrm{.}004810\mathrm{.}00380.$ a$)$ Find out whether the reaction is $1$st or $2$nd order. Validate your result please explain b$)$ Calculate the initial CA$0$ concentration of the reaction.

$2)$ and find this result also in a MATLAB