The concentration of C = 85.45%, and H = 14.44% is not obeyed by the formula

Options

A. `CH_2`
B. `C_2 H_4`
C. `C_2 H_6`
D. `C_4 H_8`

Explanation

To solve the problem regarding the concentrations of carbon and hydrogen, we will follow these steps:

### Step 1: Determine the mass percentages of carbon and hydrogen
Given:
- Percentage of Carbon (C) = 85.45%
- Percentage of Hydrogen (H) = 14.44%

### Step 2: Convert the percentages to grams
Assuming we have 100 grams of the compound:
- Mass of Carbon = 85.45 g
- Mass of Hydrogen = 14.44 g

### Step 3: Calculate the number of moles of each element
To find the number of moles, we will use the formula:
\[ \text{Number of moles} = \frac{\text{mass (g)}}{\text{molar mass (g/mol)}} \]
- Molar mass of Carbon (C) = 12 g/mol
- Molar mass of Hydrogen (H) = 1 g/mol

Calculating the moles:
- Moles of Carbon = \(\frac{85.45 \text{ g}}{12 \text{ g/mol}} = 7.12 \text{ moles}\)
- Moles of Hydrogen = \(\frac{14.44 \text{ g}}{1 \text{ g/mol}} = 14.44 \text{ moles}\)

### Step 4: Find the simplest ratio of moles
To find the simplest ratio, we divide the number of moles of each element by the smallest number of moles calculated:
- Ratio of Carbon to Hydrogen = \( \frac{7.12}{7.12} : \frac{14.44}{7.12} = 1 : 2 \)

### Step 5: Write the empirical formula
From the ratio of 1:2, the empirical formula is:
\[ \text{Empirical Formula} = CH_2 \]

### Step 6: Identify possible molecular formulas
The molecular formula can be a multiple of the empirical formula. Possible molecular formulas include:
- \(C_2H_4\) (2 times the empirical formula)
- \(C_4H_8\) (4 times the empirical formula)

### Step 7: Identify the formula that does not match
The question states that the given concentrations do not obey a certain formula. Among the options, \(C_2H_6\) does not match the calculated ratios and is therefore excluded.

### Final Answer:
The empirical formula is \(CH_2\) and the molecular formulas \(C_2H_4\) and \(C_4H_8\) are valid, while \(C_2H_6\) does not obey the given concentrations.

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