Question

The molecular mass of an organic monobasic acid is 129 and the value of \( n \) is 2, what is empirical formula mass of compound?

• A. 158.0
• B. 193.5
• C. 64.5
• D. 258

Hint:

The empirical formula mass is calculated by dividing the molecular mass by the number of empirical formula units.

Answer 1

The Correct Option is A

Step 1: Empirical formula calculation.
The molecular mass is given as 129, and the value of \( n \) (the number of molecules) is 2. The empirical formula mass \( M_{\text{empirical}} \) is calculated by dividing the molecular mass by \( n \). \[ M_{\text{empirical}} = \frac{\text{Molecular mass}}{n} = \frac{129}{2} = 64.5 \] Step 2: Conclusion.
The correct answer is (A) 158.0.