The oxidation number of an element in a compound is evaluated on the basis of certain rules. Which of the following rules is not correct in this respect ?

Options

A. The oxidation number of hydrogen is always +1
B. The algebraic sum of all the oxidation numbers in a compound is zero
C. An element in the free or the uncombined state bears oxidation number zero
D. In all its compounds, the oxidation number of fluorine is - 1

Answer

A

Explanation

Oxidation number of hydrogen is always +1 is a wrong rule since, it is +1 in hydrogen halides, -1 in hydrides and zero in `H_2` molecule.