$*26-28.$ The sodium salt of $2-$quinizarinsulfonic acid $($NaQ$)$ forms a complex with $A{l}^{3+}$ that absorbs strongly at $560nm.{?}^{18}$ The data collected on this system are shown in the accompanying table. $($a$)$ Find the formula of the complex from the data. In all solutions,

$c_{Al}=3\mathrm{.}7{10}^{-5}M,$ and all measurements were made in $1\mathrm{.}00-$cm cells. $($b$)$ Find the molar absorptivity of the complex.

$\backslash$table$[[c_Q,M,A_{560}($Explan$)$