$A$ metal which does not react with nitrogen is

$A$ horizontal force of $10\, N$ is necessary to just hold a block stationary against a wall. The coefficient of friction between the block and the wall is $0.2$. The weight of the block is ........ $N$.

Among $Ni(CO)_4$,$[Ni(CN)_4]^{2-}$ and $[NiCl_4]^{2-}$,which of the following statements is correct regarding their magnetic properties?

Which of the following substances would quickly absorb oxygen?

The scientific name of the earthworm is ....

Identify $acetaldoxime$.