Assertion : $Pb{I}_4$  is not known probably because of the oxidising power of Pb(IV) and reducing power of $I^{-}$.

Reason :  Iodide stabilizes higher oxidation state.

Assertion : $P_4{O}_{10}$ is not used to dry $N{H}_3$.

Reason : $P_4{O}_{10}$ is acidic and $N{H}_3$ is basic.

Assertion : $HN{O}_3$  is stronger acid than $HN{O}_2$.

Reason : In $HN{O}_3$ there are two nitrogen to oxygen bonds where as in $HN{O}_2$ there is only one.

Assertion : $HN{O}_3$ oxides sulphur to $H_{2}S{O}_4$  acid ( S + VI) but only oxidizes selenium to $H_{2}Se{O}_3$ ( Se + IV ).

Reason : In Selenium atoms, the electrons are more tightly held by the nucleus on account of increased nuclear charge.

Assertion : Sulphur dioxide is more powerful reducing agent in alkaline medium than in acidic
medium.

Reason :  Sulphur dioxide reacts with hydrogen sulphide in presence of moisture and sulphur is
precipitated.

Assertion : $S{F}_6$ is used as a gaseous insulator in high voltage generators.

Reason :  It is inert and has good dielectric properties.

Assertion : Finely divided iron does not form ferric chloride with hydrochloric acid.

Reason :  Hydrochloric acid produces hydrogen gas with iron.

Assertion : $Xe{F}_6$ reacts with small quantity of water to form $XeO{F}_4$.

Reason : $Xe{F}_6$ reacts with glass and form $XeO{F}_4$.

Assertion :  In trimethyalamine (N(CH₃)₃), the nitrogen has a pyramidal geometry, wheres in trisilylamine (N(SiH₃)₃), it has a planer geometry.

Reason : In trimethylamine, nitrogen shows sp³ hybridization while in trisilyamine it shows sp² hybridization.

Assertion : Most of the known noble gas compounds are those of xenon.

Reason : The ionisation enthalpy of xenon is very close to that of oxygen.