Identify the final product $Y$ in the following reaction sequence:
$CH_2 = CH_2$ $\xrightarrow{O_2/Ag} X$ $\xrightarrow{473 \ K} Y$

The heat evolved in the combustion of methane is given by the following equation:
$CH_{4(g)} + 2O_{2(g)} \to CO_{2(g)} + 2H_2O_{(l)};$
$\Delta H = -890.3 \, kJ$
How many grams of methane would be required to produce $445.15 \, kJ$ of heat of combustion?

$20 \text{ mL}$ of $0.1 \text{ M}$ acetic acid is mixed with $50 \text{ mL}$ of potassium acetate. $K_a$ of acetic acid $= 1.8 \times 10^{-5}$ at $27^\circ \text{C}$. Calculate the concentration of potassium acetate if the $pH$ of the mixture is $4.8$. (in $\text{ M}$)

If the standard deviation of the numbers $-1, 0, 1, k$ is $\sqrt{5}$ where $k > 0,$ then $k$ is equal to

Which of the following is an amphoteric oxide?

The principal section of a glass prism is an isosceles triangle $ABC$ with $AB=AC$. The face $AC$ is silvered. $A$ ray of light is incident normally on the face $AB$ and after two reflections,it emerges from the base $BC$ perpendicular to the base. Angle $BAC$ of the prism is (in $^{\circ}$)