Which was the first commercially developed insecticide?

When a sound wave of wavelength $\lambda$ is propagating in a medium,the maximum velocity of the particle is equal to the wave velocity. The amplitude of the wave is:

If the number of diagonals of a regular polygon is $35$,then the number of sides of the polygon is

$A$ big liquid drop splits into $n$ similar small drops under isothermal conditions. Then, in this process:

Which of the following reactions can produce aniline as the main product?

$10 \ g$ of hydrogen and $64 \ g$ of oxygen were filled in a steel vessel and exploded. The amount of water produced in this reaction will be ........... $mol$.