Answer:
Molecular formula = C₆H₄Cl₂
Explanation:
Given data:
Percentage of hydrogen = 2.7%
Percentage of carbon = 49%
Percentage of chlorine = 48.2%
Molar mass of compound = 150 g/mol
Molecular formula = ?
Solution:
Number of gram atoms of H = 2.7 / 1.01 = 2.67
Number of gram atoms of Cl = 48.2 / 16 = 1.36
Number of gram atoms of C = 49 / 12 = 4.08
Atomic ratio:
C : H : Cl
4.08/ 1.36 : 2.67/1.36 : 1.36/1.36
3 : 2 : 1
C : H : Cl = 3 : 2 : 1
Empirical formula is C₃H₂Cl.
Molecular formula:
Molecular formula = n (empirical formula)
n = molar mass of compound / empirical formula mass
Empirical formula mass = 12×3 + 1.01 ×2 + 35.5 = 73.52 g/mol
n = 150 / 73.52
n = 2
Molecular formula = n (empirical formula)
Molecular formula = 2 (C₃H₂Cl)
Molecular formula = C₆H₄Cl₂