Question

74.5 g of metallic chloride contains 35.5g of chlorine. The equivalent mass of the metal is:
a.) 19.5
b.) 35.5
c.) 39.0
d.) 78.0

Answer 1

Hint: For finding the equivalent weight of metal we have to find how much chlorine reacts with that metal to form metal chloride. And all information is given in the question.

Complete step by step solution:
It is given: mass of metal chloride= 74.5 g
mass of chlorine = 35.5 g

Thus mass of metal = mass of metal chloride - mass of chlorine= (74.5-35.5) = 39 g
Here, we know that equivalent weight is the weight of a substance which reacts with 35.5 gram of chlorine.
From the above calculation we can say that 39 gram of metal reacts with 35.5 g of chlorine.
Thus the equivalent weight of metal is 39 gram.

Additional information:
We know that equivalent weight is also known as "gram equivalent". Which is "atomic or molecular weight” divided by the “valence”.

From the given,
Weight of metallic chloride = 74.5
Weight of chlorine = 35.5
Weight of metal = 74.5 - 35.5 = 39
Equivalent weight will be calculated by the following formula:
Equivalent weight of the metal = \[~\dfrac{weight\text{ }of\text{ }metal~}{weight\text{ }of\text{ }chlorine}\times 35.5\]
  =\[~\dfrac{39~}{35.5}\times 35.5\]
Equivalent weight of the metal = 39 grams
So, the correct answer is option “C”.

Note: So, this formula or method of calculating equivalent weight of metal we can use for any metal with respect to chlorine. And here no need to apply the second method. You will get the answer only by using the first method.