Question

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

• The oxidation number of hydrogen is always +1.

• The algebraic sum of all the oxidation numbers in a compound is zero.

• An element in the free or the uncombined state bears oxidation number zero.

• In all its compounds, the oxidation number of fluorine is – 1.

Answer 1

The oxidation number of hydrogen is always +1.

Explanation:

Oxidation number of hydrogen is – 1 in metal hydrides like \[\ce{NaH}\].