Which of the following concepts best explains why $o-$nitrophenol is more volatile than $p-$nitrophenol?

Let $x+y=k$ be a normal to the parabola $y^2=12x$. If $p$ is the length of the perpendicular from the focus of the parabola onto this normal,then $4k-2p^2$ is equal to

In the reaction sequence,$C_2H_5Cl + KCN$ $\xrightarrow{C_2H_5OH} X$ $\xrightarrow[\Delta]{H_3O^+} Y$. What is the molecular formula of $Y$?

Which of the products is formed when acetone is reacted with barium hydroxide solution?

$A$ student has to answer $10$ out of $13$ questions in an examination,choosing at least $5$ questions from the first $6$ questions. The number of choices available to the student is:

Ecdysone is produced by