Which of the following does not produce $NO_2$ gas with concentrated $HNO_3$?

The minimum temperature required for a non-catalytic reaction between $N_2$ and $O_2$ is (in $K$)

The most common minerals of phosphorus are

First ionisation enthalpy values of first four group $15$ elements are given below. Choose the correct value for the element that is a main component of apatite family $:$

Which blue liquid is obtained on reacting equimolar amounts of two gases at $-30\,^oC$?

Which of the following oxides is paramagnetic?