What is the meaning of the two in ethyl alcohol, C_2H_5OH?

May 11, 2016

The subscript gives the number of atoms in the chemical formula.

Explanation:

Ethyl alcohol, ${C}_{2} {H}_{5} O H$, is a carbon chain of $2$ carbon atoms, with an oxygen chemically bound to one end of the chain.

We could represent this is in the formulation:

${H}_{3} C - C {H}_{2} - O H$

Carbon 1 (from the left) is bound to 3 hydrogens and to C2. C2 is bound to C1, 2 hydrogens and an oxygen atom. Because it is easier to write ${C}_{2} {H}_{5} O H$ than the whole chain, it is a convenient representation.