Question

1.5 g of $CdC{{l}_{2}}$ was found to contain 0.9 g of Cd. Calculate the atomic weight of Cd.
(A) 118
(B) 112
(C) 106.5
(D) 53.25

Answer 1

Atomic weight is the mass of an atom. The SI unit of atomic mass is kilogram but it is usually expressed in the non SI unit Dalton and 1 Dalton is equal to $\dfrac{1}{12}th$ of the mass of carbon 12 atoms at rest. Cadmium is a zinc by-product that has the potential to alter the health of a human being and plants when they come in contact with them.

Complete step by step solution:
Given in the question:
1.5 g of $CdC{{l}_{2}}$ was found to contain 0.9 g of Cd
And we can say that 1.5 g of $CdC{{l}_{2}}$ was found to contain 0.9 g of Cd
If 0.9 gram of cd is present then the mass of chlorine = $1.5-0.9$= 0.6 grams of chlorine
We can say that 0.6 grams of chlorine combines with 0.9 grams of cadmium
Hence 71 grams of chlorine will combine with = $\dfrac{0.9}{0.6}(71)$g of Cd
71 grams of chlorine will combine with= 106.5 g of Cd
Hence the atomic weight of Cd = 106.5 g

The correct answer is option (C) i.e. when 1.5 g of $CdC{{l}_{2}}$ was found to contain 0.9 g of Cd. The atomic weight of Cd = 106.5 g.

Note: Cadmium is a silvery white metal which has an extremely soft texture hence this metal can be molded into any form without breaking or cracking it. It is used in the power stations in the metalworking industries. It is also used in formation of alloys jewelry along with ceramic and enamels. Cadmium is present in mobile phones, cameras, computers and other devices.