Which of the following is used as white pigment
$Ti{O_2}$
${V_2}{O_5}$
$CuO$
$HgO$
Which of the following pair of ions may exhibit same colour
The form of iron having the highest carbon content is
The $3d$ metal ions form coloured compounds because the energy corresponding to the following lies in the visible range of electromagnetic spectrum
The compound which does not show paramagnetism is :-