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

The addition of metals like $Cr$,$Mn$,$W$ and $Ni$ to ordinary steel makes it

Given below are two statements:
Statement $I :$ Potassium permanganate on heating at $573 \ K$ forms potassium manganate.
Statement $II :$ Both potassium permanganate and potassium manganate are tetrahedral and paramagnetic in nature.
In the light of the above statements,choose the most appropriate answer from the options given below.

If the magnetic moment $(\mu)$ of an oxide of manganese is $4.9 \ BM$,which oxide is it?

On heating $KMnO_4$,which one of the following is not formed?

Correct statement for $CeO_2$ is/are:
$1$. It is diamagnetic in nature.
$2$. It is a good oxidising agent.
$3$. It is a colourless compound.