Find oxidation number of oxygen in $Ca{O}_2$.

Q. Find the oxidation number of Oxygen in $CaO$.

Q.

Assign oxidation numbers to the underlined elements in each of the following species:

(a) NaH₂PO₄ (b) NaHSO₄ (c) H₄P₂O₇ (d) K₂MnO₄

(e) CaO₂ (f) NaBH₄ (g) H₂S₂O₇ (h) KAl(SO₄)₂.12 H₂O

Q. Assign oxidation number to the underlined elements in each of the following species.
(i)${NaH}_2\underset{–}{P}{O}_4$
(ii)$NaH\underset{–}{S}{O}_4$
(iii)$H_4{\underset{–}{P}}_2{O}_7$
(iv)$H_2{\underset{–}{S}}_2{O}_7$
(v)$Ca{\underset{–}{O}}_2$
(vi)$Na\underset{–}{B}{H}_4$
(vii)$KAl{\left({\underset{–}{SO}}_4\right)}_2.12H_{2}O$
(viii)$\underset{–}{C{r}_2}{O}_7^{2-}$

Q. Oxidation number of $Cr$ in $Cr{O}_{2}C{l}_2$ is $+6$. Oxidation number (per atom) of oxygen is: