Which of the following is not a cyclic oxyacid?

Nitrogen dioxide cannot be prepared by heating:

Assertion $(A)$: In group $15$ elements, nitrogen does not form pentahalides.
Reason $(R)$: Nitrogen can exhibit $+5$ oxidation state.
The correct option among the following is:

Which one of the following statements is correct with respect to basic character?

Explain why $NH_3$ is basic while $BiH_3$ is only feebly basic.

Consider the following Assertion $(A)$: Phosphorus can form both phosphorus$(III)$ and phosphorus$(V)$ chlorides, but nitrogen cannot form nitrogen$(V)$ chloride. Reason $(R)$: The electronegativity of nitrogen is more than that of phosphorus. The correct answer is