$KMnO_4$ decomposes on heating at $513 \ K$ to form $O_2$ along with

$MnO^{-}_4$ is of intense pink colour,though $Mn$ is in $(+7)$ oxidation state,it is due to

Which among the following statements is incorrect for interstitial compounds?
$1$. They are very hard and rigid
$2$. They have higher melting point than pure metal
$3$. They do not show conductivity
$4$. They are chemically inert

Which from the following is the general formula of the compound obtained when lanthanoid $(Ln)$ reacts with carbon at elevated temperature?

Which oxide of $Mn$ is acidic in nature?

When dilute $H_2SO_4$ is added to an aqueous solution of potassium chromate,the yellow color of the solution turns to orange. What does this indicate?