Which of the following reactions proceeds with a moderate speed?
Answer & explanation
Correct answer: option 4
The correct answer is Option (4) → Hydrolysis of starch
Reactions differ widely in speed.
Ionic reactions such as the precipitation of silver chloride take place almost instantaneously.
Rusting of iron is very slow, and the change of diamond into graphite is so slow that it is not noticed at all.
Reactions such as the hydrolysis of starch and the inversion of cane sugar lie in between: they go at a moderate speed.
NCERT (2026-27 edition):
3.1 Rate of a Chemical Reaction – “Some reactions such as ionic reactions occur very fast, for example, precipitation of silver chloride occurs instantaneously by mixing of aqueous solutions of silver nitrate and sodium chloride. On the other hand, some reactions are very slow, for example, rusting of iron in the presence of air and moisture. Also there are reactions like inversion of cane sugar and hydrolysis of starch, which proceed with a moderate speed.”