The oxidation states of $P$ in $H_{4}P_{2}O_{7}$,$H_{4}P_{2}O_{5}$ and $H_{4}P_{2}O_{6}$,respectively,are:

The difference in oxidation state of chromium in chromate and dichromate salts is $....$ .

What are the oxidation numbers of the underlined elements in each of the following and how do you rationalize your results?
$(1)$ $K\underline{I_3}$
$(2)$ $H_2\underline{S_4}O_6$
$(3)$ $\underline{Fe_3}O_4$
$(4)$ $\underline{C}H_3\underline{C}H_2OH$
$(5)$ $\underline{C}H_3\underline{C}OOH$

What is the oxidation number of $P$ in $Ba(H_2PO_2)_2$?

$A$ compound contains three elements $A$,$B$,and $C$. If the oxidation numbers are $A = +2$,$B = +5$,and $C = -2$,the possible formula of the compound is:

Which one of the following does not have an underlined atom with a fractional oxidation state?