Quinine is a natural product extracted from the bark of the cinchona tree, which is native to south america. quinine is used as an antimalarial agent. when 1.53 g of quinine is dissolved in 25.0 g of cyclohexane, the freezing point of the solution is lowered by 3.93 °c. the freezing point and kf constant for cyclohexane can be found here. calculate the molar mass of quinine.

The formula for freezing point depression is: ΔTf = mkfi 

Where:
kf = freezing point constant 
i = Van't Hoff factor which in this case is 1 
m = molality (moles of solute/kg of solvent) 
ΔTf = temperature change 

ΔTf is 3.93°C, the molality is the amount of solute Quinine in the solvent cyclohexane. Moles cannot be calculated, therefore substitution of moles with g/mm is needed.
moles is g/m, therefore molality is equal to (g/mm)/kg 

Calculations:

molality = (0.153/mm)/0.025 = 6.12/mm 

3.93 = 6.12/mm(20.8)

mm = (6.12/3.93)(20.8) = 32.39 g/mol

first one is the correct answer

chemical digestion occurs in the stomach were hcl and pepsin forms chyme, the mouth in which salivary amylase breaks down starch to form bolus, and the small intestine specifically the duodenum.