Oxidation Number — Prelims Questions

What is the oxidation number of sulfur in $H_2SO_5$ (Caro's acid)?

Which of the following compounds contains an element with a fractional oxidation number?

In which of the following compounds does hydrogen exhibit an oxidation number of -1?

Identify the oxidizing agent in the following reaction: $2KMnO_4 + 5H_2C_2O_4 + 3H_2SO_4 \rightarrow K_2SO_4 + 2MnSO_4 + 10CO_2 + 8H_2O$

What is the oxidation number of phosphorus in $H_3PO_2$?

Which of the following statements about oxidation number is INCORRECT?