Question

Why is biphenyl soluble in petroleum ether, but triphenylmethanol is not?

Answer 1

Petroleum ether is volatile liquid of hydrocarbon (it does not contain ether) . Ph-Ph (biphenyl) is a hydrocarbon so it should be soluble in Non-polar medium, i.e. like dissolve like principle .

(Ph)3C-OH (triphenylmethanol) is soluble in ethanol, diethyl ether etc but insoluble in petroleum ether because of the polar nature of the compound .

We can refer the Rf values for these two compounds , Rf value of biphenyl is more than triphenylmethanol . Hence triphenylmethanol is more polar .