What is the chemical formula of sodium pyrophosphate?

The cyanamide process is used in the formation of:

Which of the following is $NOT$ a property of red phosphorus?

In the nitrogen group,as we move from $N$ to $Sb$,the $H-M-H$ bond angle in the hydrides approaches $90^o$ because ......

Give the disproportionation reaction of $H_3PO_3$.

Choose the correct statement$(s)$ among the following.
$A$. $SnCl_2 \cdot 2 H_2O$ is a reducing agent.
$B$. $SnO_2$ reacts with $KOH$ to form $K_2[Sn(OH)_6]$.
$C$. $A$ solution of $PbCl_2$ in $HCl$ contains $Pb^{2+}$ and $Cl^{-}$ ions.
$D$. The reaction of $Pb_3O_4$ with hot dilute nitric acid to give $PbO_2$ is a redox reaction.