Question

Two oxides of metals A and B are isomorphous. The metal A whose atomic mass is 52, forms a chloride whose vapour density is 79. The oxide of the metal B contains 47.1% oxygen. Calculate the atomic mass of B.

• A. 26.95
• B. 30
• C. 29.5
• D. 29.9

Answer 1

The correct option is A 26.95

Formula of first metal chloride is $MC{l}_x$

Molar mass = 52 + 35.5 x = 158

Solving, x = 3

Second oxide is $M_2{O}_3$

% $O=47.1=\frac{48\times 100}{2A+48}$

where A is atomic mass of M

A = 26.95