Which of the following elements forms a strongly acidic oxide?

Pure $HNO_3$ is a colorless liquid,but it turns light brown in the presence of light. This is due to its decomposition into which of the following substances in small amounts?

$A$ pure sample of nitrogen is prepared by heating

Identify the correct orders from the following with respect to the property associated with:
$A$. $NH_3 > PH_3 > AsH_3 > SbH_3$ - Bond Angle
$B$. $NH_3 > PH_3 > AsH_3 > SbH_3$ - Basic Character
$C$. $PH_3 > AsH_3 > SbH_3 > NH_3$ - Thermal stability
$D$. $SbH_3 > NH_3 > AsH_3 > PH_3$ - Boiling point

What is the product formed when phosphorus is oxidized by concentrated nitric acid?

The number of $P=O$ and $P-P$ bonds present in the oxoacid of phosphorus,prepared by treating red $P_4$ with alkali,are respectively: