An organic compound contains 78% (by wt.) carbon and remaining percentage of hydrogen. The right option for the empirical formula of this compound is : [Atomic wt. of C is 12, H is 1]

The correct option is CH₃.

To find the empirical formula of the organic compound, we follow these step-by-step calculations:

Step 1: Calculate the mass percentage of each element
The compound contains 78% carbon by weight.
Since the remaining percentage is hydrogen, we can find the percentage of hydrogen as follows:
$\text{Percentage of Hydrogen (H)}=100-78=22\%$

Step 2: Determine the relative number of moles (atomic ratio) of each element
To find the relative number of moles, we divide the percentage weight of each element by its respective atomic weight (C = 12, H = 1):
For Carbon (C):

$\text{Relative moles of C}=\frac{78}{12}=6.5$

For Hydrogen (H):

$\text{Relative moles of H}=\frac{22}{1}=22$

Step 3: Determine the simplest whole-number ratio
We divide the relative number of moles of each element by the smallest value obtained (which is 6.5):
For Carbon (C):

$\frac{6.5}{6.5}=1$

For Hydrogen (H):

$\frac{22}{6.5}\approx 3.38\approx 3$

Rounding to the nearest whole number based on the standard empirical options, the simplest whole-number ratio of C to H is approximately 1 : 3.

Therefore, the empirical formula of the compound is CH₃.