Which of the following elements is most metallic?

On heating lead $(II)$ nitrate gives a brown gas $'A'$. The gas $'A'$ on cooling changes to a colourless solid $'B'$. Solid $'B'$ on heating with $NO$ changes to a blue solid $'C'$. Identify $'A'$,$'B'$ and $'C'$,write the reactions involved,and draw the structures of $'B'$ and $'C'$.

What is the chemical formula of sodium pyrophosphate?

Phosphine may be produced by adding water to

How can you synthesize nitric oxide $(NO)$ in the laboratory?

Taking stability as the factor,which one of the following represents the correct relationship?