Question

The mass percentage of an element ‘X’ in XO2 is 50%. Identify X from the options given below.

• A. Bromine
• B. Nitrogen
• C. Sulphur
• D. Silicon

Answer 1

The correct option is C Sulphur

Given:

• One molecule of XO2 contains 1 X atom, and the Mass percentage of element X is 50.04%.
• Let the molar mass of X be x.

Percentage of element X in a compound =Mass of element X present/Molar mass of the compound x 100
The molar mass of compound XO2 = x + 2(16).
And, the Mass of element X in the compound = 1x
On substituting all values in the formula,
50 % = x / (x+32) x 100
Thus, the value of x comes out to be 32g.