Question

A compound X contains 32% of A, 20% of B and remaining percentage of C. Then, the empirical formula of X is:
(Given atomic masses of A=64; B=40; C=32 u)

• A. A₂BC₂
• B. ABC₃
• C. AB₂C₂
• D. ABC₄

Answer 1

The Correct Option is B

Step 1: Calculate moles of each element:

Moles of A = $\frac{\text{Mass of A}}{\text{Atomic Mass of A}} = \frac{32}{64} = 0.5$

 

Moles of B = $\frac{\text{Mass of B}}{\text{Atomic Mass of B}} = \frac{20}{40} = 0.5$

 

Moles of C = $\frac{\text{Mass of C}}{\text{Atomic Mass of C}} = \frac{48}{32} = 1.5$

 

Step 2: Divide by smallest mole value:

Ratio: $\frac{0.5}{0.5} : \frac{0.5}{0.5} : \frac{1.5}{0.5} = 1 : 1 : 3$

 

Step 3: Empirical formula:

Empirical Formula: $ABC_3$

Answer 2

Empirical Formula Calculation for Compound X 

Step 1: Calculate the moles of A, B, and C

Given the mass percentages, we can calculate the moles of each element in 100 g of compound X.

• Moles of A: 32 g / 64 g/mol = 0.5 mol
• Moles of B: 20 g / 40 g/mol = 0.5 mol
• Moles of C: 48 g / 32 g/mol = 1.5 mol

Step 2: Determine the simplest whole number ratio

The ratio of moles of A, B, and C is:

A:B:C = 0.5 : 0.5 : 1.5 = 1 : 1 : 3

Step 3: Write the empirical formula

The empirical formula of X is: ABC₃

Step 4: Conclude

The correct answer is: ABC₃