Question

The vapour density of a chloride of an element is $39.5$. The Equivalent weight of the elements is $3.82$. The atomic weight of the element is :

• A. 15.28
• B. 7.64
• C. 3.82
• D. 11.46

Answer 1

Answer: (B)

7.64

Molecular weight of metal chloride $\left(MC{l}_x\right)=M+x\times 35.5$$=2\times V.D=2\times 39.5$$=79.0$

$M_w=E_w\times x$

Valency of metal $=x$

The atomic weight of element $=Ew\times x$

$M_{MC{l}_x}=3.82\times x+x\times 35.5=79$

$x=\frac{79}{3.82+35.5}\approx 2$

Atomic weight $=E_w\times x=3.82\times 2=7.64$