The empirical formula of octane C88​div818​ is:

A

C4
​H9
​

B

C2
​H9
​

C

C8
​div8
​

D

C3
​H3
​

To determine the empirical formula of octane, we first need to understand what an empirical formula represents. It shows the simplest whole-number ratio of the elements in a compound. In the case of octane, which has the molecular formula C8H18, we want to simplify that formula to its most basic form.

Breaking Down the Molecular Formula

The molecular formula of octane is C8H18. This indicates there are 8 carbon (C) atoms and 18 hydrogen (H) atoms. To find the empirical formula, we need to find the greatest common divisor (GCD) of the numbers of carbon and hydrogen atoms.

Finding the Greatest Common Divisor

In this case, the numbers are 8 and 18. The GCD of 8 and 18 is 2. To simplify the formula, we divide both the number of carbon atoms and hydrogen atoms by this GCD:

• Carbon: 8 / 2 = 4
• Hydrogen: 18 / 2 = 9

Formulating the Empirical Formula

After performing the division, we find that the ratio of carbon to hydrogen in its simplest form is 4:9. Therefore, the empirical formula for octane is C4H9.

Conclusion

So, among the options provided, the correct empirical formula of octane (C8H18) is C4H9. This means that the answer to your question is A, C4H9. Understanding empirical formulas is crucial because it allows chemists to quickly identify the simplest ratio of elements in a compound, which can be particularly useful in various chemical calculations and reactions.