MHT CET Chemistry Question (2026) — Solution

Step-by-step solution

The decomposition of acetaldehyde ( CH _3 CHO ) is a well-known example of a fractional order reaction. The experimentally determined rate law for this reaction is given by: Rate = k[ CH _3 CHO ]^ 1.5 Thus, the overall order of the reaction is 1.5, which is a fractional value. For the other given reactions: Decomposition of H _2 O _2 is a first-order reaction. Formation of HI from H _2 and I _2 is a second-order reaction. Reaction between NO and H _2 is a third-order reaction. Answer: CH _3 CHO (g) CH _4 (g) + CO (g)