Which of the following are used as catalysts in petroleum cracking?

The orange colour of $K_2Cr_2O_7$ and purple colour of $KMnO_4$ is due to

Name the oxometal anions of the first series of the transition metals in which the metal exhibits the oxidation state equal to its group number.

Fusion of $MnO_2$ with $KOH$ in the presence of air or an oxidizing agent like $KNO_3$ forms a colored compound. Identify the product and its color.

Which of the following is amphoteric?

The spin only magnetic moment $(\mu)$ value $(B.M.)$ of the compound with strongest oxidising power among $Mn_2O_3$,$TiO$,and $VO$ is $....$ $B.M.$ (Nearest integer).