Plz solv my que with solution ans foemula

Question

Two element A and B form compound of formula AB2 and AB4 when dissolved in 20.0g of benzene 1.0g of AB2 lowers f.pt.by 23 degree centigrate whereas 1.0g of AB4 lowers.f.pt. by 1.3 degree centigrate.The  Kf for benzene is 5.1.The atomic masses of A and B are

Answer 1

Is the freezing point depression with AB₂ really 23 degrees, or is it supposed to be 2.3 degrees? Also, one would have to know if AB₂ and AB₄ are ionic or molecular compounds so that the van't Hoff factor can be estimated. Use ∆T = imk and solve for m.