$A$ hydride of nitrogen which is acidic is

Which one of the following halogens liberates oxygen,when passed through hot concentrated $KOH$ solution?

Which one of the following animals is correctly matched with its particular named taxonomic category?

If $\overrightarrow{a}=\hat{i}+\hat{j}+\hat{k}$,$\overrightarrow{b}=\hat{i}+\hat{j}$,$\overrightarrow{c}=\hat{i}$ and $(\overrightarrow{a} \times \overrightarrow{b}) \times \overrightarrow{c}=\lambda \overrightarrow{a}+\mu \overrightarrow{b}$,then $\lambda+\mu$ is equal to:

Assertion $(A)$: Cyclohexane is the most stable cycloalkane.
Reason $(R)$: Cyclopropane and cyclobutane are less stable due to angle strain and torsional strain.
The correct answer is:

Nylon-$66$ is not a ......