You are field sampling at a contaminated site and collect a sample containing $250g$ of soil and $500mL$ of aqueous solution in a $1\mathrm{.}5L$ sealed jar $($the rest of the jar is filled with air$).$ Back in the laboratory, you measure the toluene concentration in the water as $0\mathrm{.}035M.$

a$.)$ What is the concentration of toluene in the air?

b$.)$ Given a $K_{sw},$ what would the concentration of toluene on the soil phase be$?$ Express your answer in terms of known parameters $($instead of a numerical value$).$