Question

Under what condition carboxylic acid is produced within the muscle cells?

Answer 1

Hint: Carboxylic acid, or lactate, may be a chemical byproduct of anaerobic respiration — the method by which cells produce energy without oxygen around. Bacteria produce it in yogurt and our guts. Carboxylic acid is additionally in our blood, where it's deposited by muscle and red blood cells.

Complete answer:
Under anaerobic respiration condition, carboxylic acid is produced within the muscle cells. E.g. Running for an extended duration.
Lactic acid is made and accumulated within the muscle under conditions of high energy demand, rapid fluctuations of the energy requirement and insufficient supply of $O_2$. During intense exercise sustained to fatigue muscle pH decreases to about 6.4-6.6.
Your muscle cells can produce carboxylic acid to offer you energy during difficult physical activities. This usually happens when there's not enough oxygen within the body, so carboxylic acid fermentation provides how to urge ATP without it. Lactic acidosis usually occurs due to exercise.
Lactic acid fermentation creates ATP, which may be a molecule both animals and bacteria need for energy, when there's no oxygen present. This process breaks down glucose into two lactate molecules. Then, lactate and hydrogen form carboxylic acid. Carboxylic acid fermentation provides an alternative thanks to generating energy when normal respiration isn't possible.

Note:
The rise of acidity of milk causes the formation of solid masses of milk, that is, curd. Curd contains carboxylic acid in it. So, this process is known as fermentation which is performed by some microorganisms.