C2H5OH
How many elements are there in a molecule of
Ethanol shown in the above formula?

There’s are 3 elements: Carbon, Hydrogen and Oxygen

Ethanol consists of 9 atoms:

2 Carbons
6 Hydrogens
1 Oxygen

2 + 6 + 1 = 9 atoms in total

Although the question doesn’t ask for atoms I just wanted to make things clear between them so you don’t get the numbers mixed up. Apart from that, there are 3 elements present in Ethanol.