Nitrogen gas is obtained by thermal decomposition of :

Given below are two statements :

Statement I : The pentavalent oxide of group-15 element, E₂O₅, is less acidic than trivalent oxide, E₂O₃, of the same element.

Statement II : The acidic character of trivalent oxide of group 15 elements, E₂O₃, decreases down the group.

In light of the above statements, choose most appropriate answer from the options given below :

The gas produced by treating an aqueous solution of ammonium chloride with sodium nitrite is :

Given below are two statements : one is labelled as Assertion A and the other is labelled as Reason R.

Assertion A : Fluorine forms one oxoacid.

Reason R : Fluorine has smallest size amongst all halogens and is highly electronegative.

In the light of the above statements, choose the most appropriate answer from the options given below :