From which of the following is quinine obtained?

An ideal refrigerator has a freezer at a temperature of $-13^{\circ}C$. The coefficient of performance of the refrigerator is $5$. The temperature of the air (to which heat is rejected) will be:

If $\frac{3x^2 + 5}{(x^2 + 1)^2} = \frac{a}{x^2 + 1} + \frac{b}{(x^2 + 1)^2}$,then $(a, b) = $

If ${}^n P_r = 30240$ and ${}^n C_r = 252$,then the ordered pair $(n, r)$ is equal to

Observe the following statements:
$1.$ Heavy water is harmful for the growth of animals.
$2.$ Heavy water reacts with $Al_4C_3$ and forms deuterated acetylene.
$3.$ $BaCl_2 \cdot 2D_2O$ is an example of interstitial deuterate.
The correct statements are:

The heating of $NH _4 NO _2$ at $60-70^{\circ} C$ and $NH _4 NO _3$ at $200-250^{\circ} C$ is associated with the formation of nitrogen containing compounds $X$ and $Y$, respectively. $X$ and $Y$, respectively, are