Question

Two elements a and b form compounds having formula ab2 n a v force when dissolved in 20 gram of benzene 1 gram of 82

Answer 1

Weight of compound AB2 w2 = 1 g

Weight of benzene w1= 20 g

Molar despression costant, Kf = 5.1 K

Depression in freezing ∆Tf = 2.3 K

We know that, Molar mass M2 = 1000 x w2 x kf / ∆Tf x w1

Molar mass of Compound AB2 (MAB2) = 1000X 1 x 5.1/ 2.3 x 20

= 110.87 g mol−1

Molar mass of Compound AB4 (MAB4) = 1000 x 1 x 5.1/1.3 x 20

= 196.15 g mol−1

Now, we have the molar masses of compound AB2 and compound AB4.

Let us find the atomic masses of elements A and B

Mass of MAB2 =Atomic weight of A + 2 × Atomic weight of B