Question

Which among the following branches of chemistry is concerned with the chemical effects of sound and ultrasonic waves?
(A) Petrochemistry
(B) Physical chemistry
(C) Photochemistry
(D) Photochemistry

Answer 1

Sound is the receipt of such waves and the brain's perception of them in human physiology and psychology. Ultrasound is defined as sound waves with a frequency greater than 20 kHz that are inaudible to humans. Infrasound is defined as sound waves with a frequency below 20 Hz. The hearing ranges of different animal species differ.

Complete answer:
The study of photochemistry in chemistry is focused on determining how ultrasound causes acoustic cavitation in liquids, which leads to the commencement or amplification of chemical activity in the solution. As a result, the chemical effects of ultrasound are not caused by the ultrasonic sound wave directly interacting with the molecules in the solution. The wavelengths of ultrasonic sound waves travelling through a liquid are several times longer than the molecular dimensions or the bond length between atoms in the molecule. The sound wave cannot directly impact the bond's vibrational energy, and so cannot directly raise a molecule's internal energy.
Photochemistry, on the other hand, is caused by acoustic cavitation, which is the development, growth, and implosive collapse of bubbles in a liquid. [3] Because the collapse of these bubbles is practically adiabatic, large amounts of energy accumulate inside the bubble, resulting in extraordinarily high temperatures and pressures in a small patch of the sonicated liquid. As the bubble quickly implodes, the extreme temperatures and pressures cause chemical excitation of any stuff within or extremely close to it.

Note:
Similar events may occur when liquids containing solids are exposed to ultrasonic. Cavity collapse is nonspherical when cavitation occurs at an extended solid surface, and it propels high-speed liquid jets to the surface. These jets, as well as the shock waves they generate, have the potential to harm the now very hot surface. High-velocity interparticle collisions occur in liquid-powder solutions. These impacts can alter the shape, composition, and reactivity of the surface.