Question

A metal oxide contains 20% oxygen by weight. Find the equivalent weight.

Answer 1

Hint: An oxide is a chemical compound which contains at least one oxygen atom with any another element. Oxide is an anion of oxygen represented as ${{O}^{2-}}$ .In this state the oxygen is present in -2 oxidation state and acts as an anion which carries negative charge.

Complete answer:
Equivalent weight which is also known by the name gram equivalent is defined as the mass of one equivalent which can be simplified in a manner that mass of a given substance which will combine with or we can also explain it which will displace a fixed quantity of another substance. The equivalent weight of an element can be defined as the mass which combines with or displaces 1.008 gram of hydrogen or 8.0 grams of oxygen or 35.5 grams of chlorine. These values correspond to the atomic weight which is divided by its valency.
Now we know that equivalent weight is that which combines with 8 parts by weight of oxygen.
If 20% mass is of oxygen which is given then remaining 80% mass is contributed by the metal,
Then the equivalent weight of metal can be calculated by $\dfrac{80}{20}\times 8=32$
Hence a metal oxide which contains 20% oxygen by weight then its equivalent weight will be 32 g.

Note:
Oxides can be formed due to the electronegative nature of oxygen which forms stable chemical bonds with almost all metals and they give corresponding oxides of that metal. Ratio of metal oxide tells us about how many metals and oxygen atoms are connected with each other.