Question

question 8 (10 points)
which of the following is a molecular formula for a compound with an empirical
formula of ch?
a) c2h6
b) c3h9
c) c6h6
d) c4h10
e) none of the answers is correct.

Explanation:

Step1: Recall the relationship between empirical and molecular formula

The molecular formula is an integer - multiple of the empirical formula. For the empirical formula \(CH_2\), the molecular formula should be \(C_nH_{2n}\), where \(n\) is a positive integer (\(n = 1,2,3,\cdots\)).

Step2: Check each option

• Option A: For \(C_2H_6\), if \(C_nH_{2n}=C_2H_6\), then \(2n = 6\), \(n = 3\). But \(C_2H_6\) does not follow the \(C_nH_{2n}\) pattern. The general formula for alkanes is \(C_nH_{2n + 2}\), and \(C_2H_6\) is an alkane (\(n=2\), \(2n + 2=6\)).
• Option B: For \(C_3H_9\), if \(C_nH_{2n}=C_3H_9\), then \(2n=9\), \(n = 4.5\), which is not an integer.
• Option C: For \(C_6H_6\), if \(C_nH_{2n}=C_6H_6\), then \(2n = 6\), \(n = 3\). But \(C_6H_6\) is a cyclic - aromatic compound and does not follow the \(C_nH_{2n}\) pattern.
• Option D: For \(C_4H_{10}\), if \(C_nH_{2n}=C_4H_{10}\), then \(2n = 10\), \(n = 5\). \(C_4H_{10}\) is an alkane (\(n = 4\), \(2n+2 = 10\)) and does not follow the \(C_nH_{2n}\) pattern.

Answer:

E. None of the answers is correct.