In the catalytic oxidation of ammonia,an oxide is formed which is used in the preparation of $HNO_3$. This oxide is

White phosphorus on reaction with concentrated $NaOH$ solution in an inert atmosphere of $CO_{2}$ gives phosphine and compound $(X)$. $(X)$ on acidification with $HCl$ gives compound $(Y)$. The basicity of compound $(Y)$ is

Which of the following oxides of nitrogen is isoelectronic with $CO_2$?

Zinc on reaction with concentrated nitric acid gives an oxide of nitrogen $(A)$. Zinc with dilute nitric acid gives another oxide of nitrogen $(B)$. Oxidation numbers of nitrogen in $(A)$ and $(B)$ are respectively:

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

Heating of $(NH_4)_2Cr_2O_7$ releases a gas. Which of the following also produces the same gas?