Question

LiH, HClO$_4$, O$_3$, P$_4$ Oxidation states of the elements are respectively:

• A. $-1,\ +7,\ 0,\ 0$
• B. $+1,\ +7,\ -1,\ 0$
• C. $-1,\ +5,\ -1,\ +3$
• D. $+1,\ +5,\ 0,\ 0$

Hint:

In compounds with metals like LiH, hydrogen can have an oxidation state of $-1$. Always check for elemental forms — their oxidation state is $0$.

Answer 1

The Correct Option is A

• In LiH, H is less electronegative than Li, so H has an oxidation state of $-1$.
• In HClO$_4$, Cl is in the +7 oxidation state to balance four $-2$ from oxygen and $+1$ from hydrogen.
• O$_3$ is elemental oxygen, so the oxidation state is $0$.
• P$_4$ is elemental phosphorus, so the oxidation state is $0$.