Which of the following statements about $\;Na_{2}O_{2}\;$ is not correct ?

Question

(a) It is diamagnetic in nature (b) It is a derivative of $\;H_{2}O_{2}\;$ (c) $\;Na_{2}O_{2}\;$ oxidises $\;Cr^{3+}\;$ to $\;CrO_{4}^{-}\;$ in acid medium (d) It is the super oxide of sodium