Which of the following oxides of nitrogen is not a common pollutant in the atmosphere?

Identify the correct order$(s)$ among the following:
$a. NH_3 > PH_3 > AsH_3$ (Thermal stability)
$b. NH_3 < PH_3 < AsH_3$ (Reducing power)
$c. NI_3 > NBr_3 > NCl_3$ (Lewis basic character)
$d. N_2O_5 > P_2O_5 > As_2O_5$ (Acidic character)
Select the correct option:

In the Haber process,hydrogen is obtained by reacting methane with steam in the presence of a $NiO$ catalyst. This process is known as steam reforming. Why is it necessary to remove $CO$ when ammonia is obtained by the Haber process?

Which of the following is also called as nitrogen sesquioxide?

When phosphine is passed through an aqueous solution of copper sulphate,the product produced is:

Of the different allotropes of phosphorus,the one which is most reactive is