During hydrolysis, must be added before the bonds can be broken. (look at flash animation on hydrolysis)

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)

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