In which of the following is the $P - O - P$ bond present?

Which of the following lead oxides is $Sindhur$?

There is very little difference in acid strength in the series $H_3PO_4$,$H_3PO_3$,and $H_3PO_2$ because

The $15^{th}$ group of the periodic table contains elements $N, P, As, Sb,$ and $Bi$. As we move from $N$ to $Bi$,how do the oxides with the general formula $E_2O_3$ behave?

Which of the following combines with $Fe(II)$ ions to form a brown complex?

Which of the following exhibits the highest solubility in water?