Coagulants $/$ dosing Q#$8-10$

$8.$ When alum $($aluminum sulfate$)$ is added to natural alkaline water as a coagulant, what insoluble product is expected to form?

$9.$ If water has a $pH$ of $7\mathrm{.}0,$ would addition of $27m\frac{g}{L}FeC{l}_3*6H_{2}O$ be expected to result in sweep coagulation? $($hint: see FE eqn book pg $343)$

$10.$ If ferric chloride is dosed at the concentration specified in the preceding problem, what mass of $FeC{l}_3*6H_{2}O$ should be added on a daily basis when treating $15$ MGD of water?