Which among the following is a pair of monocarboxylic acids?

$A$ bag contains $n$ white and $n$ black balls. Pairs of balls are drawn at random without replacement successively,until the bag is empty. If the number of ways in which each pair consists of one white and one black ball is $14400$,then $n$ is equal to

If one of the lines of the pair $ax^2 + 2hxy + by^2 = 0$ bisects the angle between the positive directions of the axes,then $a, b, h$ satisfy the relation:

........ of a reaction cannot be determined experimentally.

In $YDSE$ with two identical slits, when the upper slit is covered with a transparent sheet of mica, the second-order minima is observed above the center of the screen and the second-order maxima below it. Which of the following cannot be a possible value of the phase difference caused by the mica sheet?

The equation of the pair of lines passing through the origin whose sum and product of slopes are respectively the arithmetic mean and geometric mean of $4$ and $9$ is