Answer:
Option-A (BaTiSi₃O₉)
Solution:
Step 1: Calculate Moles of each Element;
Moles of Ba = %Ba ÷ At.Mass of Ba
Moles of Ba = 33.21 ÷ 137.33
Moles of Ba = 0.241 mol
Moles of Ti = %Ti ÷ At.Mass of Ti
Moles of Ti = 11.58 ÷ 47.88
Moles of Ti = 0.241 mol
Moles of Si = %Si ÷ At.Mass of Si
Moles of Si = 20.38 ÷ 28.09
Moles of Si = 0.725 mol
Moles of O = %O ÷ At.Mass of O
Moles of O = 34.83 ÷ 16.0
Moles of O = 2.176 mol
Step 2: Find out mole ratio and simplify it;
Ba Ti Si O
0.241 0.241 0.725 2.176
0.241/0.241 0.241/0.241 0.725/0.241 2.176/0.241
1 1 3 9
Hence, Empirical Formula = BaTiSi₃O₉
Step 3: Calculating Molecular Formula:
Molecular formula is calculated by using following formula,
Molecular Formula = n × Empirical Formula ---- (1)
Also, n is given as,
n = Molecular Weight / Empirical Formula Weight
Molecular Weight = 413.44 g.mol⁻¹
Empirical Formula Weight = 137.33 (Ba) + 47.88(Ti) + 28.09 (Si₃) + 16 (O₉) = 413.48 g.mol⁻¹
So,
n = 413.44 g.mol⁻¹ ÷ 413.48 g.mol⁻¹
n = 1
Putting Empirical Formula and value of "n" in equation 1,
Molecular Formula = 1 × BaTiSi₃O₉
Molecular Formula = BaTiSi₃O₉
