試題詳解

11. A quantity of ₂ g of C₆H₅COOH dissolved in 25 g of benzene shows a depression in freezing point equal to 1.96 K. Molar depression constant for benzene is 4.9 K.kg/mol. What is the percentage association of acid if it forms double molecules (dimer) in solution?
(A) 39%,
(B) 78%,
(C) 61%,
(D) 19.5%,
(E) 56%.