An organic compound has `% C = 68.85, % H = 4.92 and % O = 26.23` (by mass). Number of carbon atoms present in the Empirical Formula of it is ………….

Options

A. `5`
B. `6`
C. `7`
D. `2`

Explanation

To solve the question regarding the organic compound with given mass percentages of carbon, hydrogen, and oxygen, we will follow these steps:

### Step 1: Write down the given percentages
We have:
- % C = 68.85
- % H = 4.92
- % O = 26.23

### Step 2: Assume a total mass for the compound
Assume the total mass of the compound is 100 g. This assumption simplifies our calculations since the percentages can be directly treated as grams:
- Mass of C = 68.85 g
- Mass of H = 4.92 g
- Mass of O = 26.23 g

### Step 3: Calculate the number of moles of each element
Using the molar masses:
- Molar mass of C = 12 g/mol
- Molar mass of H = 1 g/mol
- Molar mass of O = 16 g/mol

Calculating the moles:
- Moles of C = 68.85 g / 12 g/mol = 5.7375 moles
- Moles of H = 4.92 g / 1 g/mol = 4.92 moles
- Moles of O = 26.23 g / 16 g/mol = 1.63875 moles

### Step 4: Determine the smallest number of moles
The smallest number of moles is for oxygen, which is approximately 1.63875 moles.

### Step 5: Divide all mole values by the smallest number of moles
Now, we will divide each mole value by the smallest number (1.63875):
- Ratio of C = 5.7375 / 1.63875 ≈ 3.5
- Ratio of H = 4.92 / 1.63875 ≈ 3
- Ratio of O = 1.63875 / 1.63875 = 1

### Step 6: Convert to whole numbers
To convert to whole numbers, we multiply all ratios by 2 (since 3.5 is not a whole number):
- C: 3.5 * 2 = 7
- H: 3 * 2 = 6
- O: 1 * 2 = 2

### Step 7: Write the empirical formula
The empirical formula based on the whole number ratios is:
C₇H₆O₂

### Step 8: Determine the number of carbon atoms in the empirical formula
From the empirical formula C₇H₆O₂, we can see that the number of carbon atoms is 7.

### Final Answer
The number of carbon atoms present in the empirical formula is **7**.

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