Number of hydrogen atoms per molecule of a hydrocarbon A having 85.8 % carbon is ___________
(Given: Molar mass of A = 84 g mol)
(Given: Molar mass of A = 84 g mol)
Show answer and solution
Answer: 12
Solution
Carbon % = 85.8%, so hydrogen % = 14.2%
Moles of C per molecule = (85.8/100 × 84)/12 = 72/12 = 6
Moles of H per molecule = (14.2/100 × 84)/1 = 11.928 ≈ 12
So the molecular formula is C₆H₁₂ (molar mass = 72 + 12 = 84 ✓), and the number of hydrogen atoms per molecule is 12.
Moles of C per molecule = (85.8/100 × 84)/12 = 72/12 = 6
Moles of H per molecule = (14.2/100 × 84)/1 = 11.928 ≈ 12
So the molecular formula is C₆H₁₂ (molar mass = 72 + 12 = 84 ✓), and the number of hydrogen atoms per molecule is 12.
[JEE Main 2023 · 25 Jan · Shift 2]