The correct answer is water.
During hydrolysis, _____water______ must be added before the bonds can be broken.
For example, sucrose undergoes hydrolysis to break into glucose and fructose. Here sucrose is a disaccharide and glucose and fructose are monosaccharides.
Sucrose + H₂O → glucose + fructose
Esters are formed by the combination of carboxylic acid and alcohol.
But the hydrolysis of ester causes the release of carboxylic acid and alcohol.
RCOOR'(ester) + H₂O → RCOOH(carboxylic acid) + R'OH(alcohol)