Question

$71$ g of chlorine combines with a metal giving $111$ g of its chloride. The chloride is isomorphous with $MgC{l}_2.6H_{2}O$. The atomic mass (in amu) of the metal is :

• A. $20$
• B. $30$
• C. $40$
• D. $69$

Answer 1

Answer: (C)

$40$

Weight of $C{l}_2=$ $W_{C{l}_2}=71$ g

Weight of metal $=W_M=111-71=40$ g

$E_M=\frac{W_M\times 35.5}{W_{C{l}_2}}=\frac{40\times 35.5}{71}=20$

Valency of metal will be two according to isomorphous.

$A_W=E_M\times 2=20\times 2=40$

Hence, the atomic mass is $40$ amu.