Question

What evidence do you have that you actually isolated limonene? If Ig of limonene dissolved has been dissolved into 10mL of isopropanol solution. The optical rotation is 12.5. what is specific rotation, presuming path length to be Idm. At 60°C vapor pressure of limonene is 125 pa, and remaining is water vapor (latm 101kpa). Find the mole % of each component.

Answer 1

Part 1.

Formula: Specific rotation = optical rotation/(concentration * path length)

Here, the concentration of the limonene solution = 1 g/10 mL = 0.1 g/mL

i.e. The specific rotation of limonene = 12.5^o/(0.1 g/mL * 1 dm) = 125 deg.mL/g.dm

Part 2.

The mole % of limonene = (0.125 kPa/101 kPa)*100 = 0.124

Therefore, the mole % of water vapor = 100-0.124 = 99.876