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 number in a compuound is zero
C. An element in the free or the uncombined state bears oxidation number zero
D. In all of its compound, the oxidation number of fluorine is `-1`

Answer

A

Explanation

Oxidation number of hydrogen is `+1` except in ionic hydrides, where it is `-1`.