Question

Select the correct statement below.

1.         The percent composition (by mass) is the same for each element in that
                           compounds empirical and molecular formulas.
2.         Three different compounds having the same percent composition and the same
                           molar mass will also have the same empirical formula.
3.         An element with the largest atomic mass is always the element present in the
                           highest percentage by mass in a compound.
4.         A and B are correct
5.          A, B, and C are correct

Answer 1

The correct option is D, A and B are correct.

For option A: we can take the example: molecular formula- C₆H₁₂O₆    Empirical formula- CH₂O

now when we calculate the percentage of each element that will remain the same in both the molecule.

For option 2: compounds having Same percentage composition and molar mass then they will have the same empirical formula that is also correct.

For option 3: To explain this concept I will take an example. H₂SO₄ in this molecular atomic mass of Sulfur is 32 atomic mass of oxygen is 16. But when we calculate the percentage composition then that will be more for oxygen not for sulfur. therefor option 3 is incorrect.

Hence the correct answer is D.