Question

An oxide of metal has 20% oxygen, the equivalent weight of metal is?
A. 32
B. 48
C. 40
D. 52

Answer 1

Equivalent weight for a given substance is defined as the mass which associates with or displaces the fixed amount of other substances. For example: 2 gm of Chlorine displaces 8 gm of oxygen molecules. For the given question we will use the relationship between the mass and the equivalent weight of the metal.

Complete step by step answer:
As we all know the equivalent weight $(E)$ is given by $E = \dfrac{{{\text{mass of metal}}}}{{{\text{mass of oxygen}}}}{\text{ = }}\dfrac{{{\text{equivalent weight of metal}}}}{{{\text{equivalent weight of oxygen}}}}$
As per the given question, oxygen in oxide= 20%,
Which means there will be 20 grams of its composition present in 100 grams of metal oxide.
Therefore,
${\text{Mass of metal (M) = Mass of oxide - Mass of oxygen}}$
Mass of oxide = 100 gm
Mass of oxygen = 20 gm
$\Rightarrow {\text{M = 80 gm}}$
By applying the formula of equivalent weight as stated above we get, and substituting the equivalent weight of oxygen which is 8 gm we get
$E = \dfrac{{80}}{{20}} = \dfrac{{{\text{equivalent weight of metal}}}}{8}$
$\Rightarrow E = 32$

Therefore, the correct option is A. .

Additional information:
Metal oxides have a wide range of applications as sensors and biosensors and play an important role as catalysts in certain chemical reactions, increasing their rate of reaction. They are known for their basic nature, as in reaction with the water molecule they form the bases.

Note: The equivalent weight of certain elements in the periodic table is fixed and they can be used to find the weight of other substances formed by the association of different elements. Equivalent weight is also known as equivalent gram equivalent and is alternatively defined as the equivalent mass which will interact with or associate or displace the element with constant molecular weight from the periodic table.