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Chemistry · 2025 · 2 marks
CBSE 2025 · Region 5 · Set 3 · Q19
(a) Give any two differences between order and molecularity of a reaction. (b) For a reaction X + Y → Z, in which both X and Y follow first order…
(a)
Give any two differences between order and molecularity of a reaction.
(b)
For a reaction $\displaystyle \mathrm{X}+\mathrm{Y} \rightarrow \mathrm{Z}$, in which both X and Y follow first order kinetics; if the concentration of X is increased $\displaystyle 2$ times and concentration of Y is increased $\displaystyle 3$ times, how does it affect the rate of reaction?
Marking-scheme solution
(a)
Order of a reaction
Molecularity
1.Experimental quantity
1.Theoretical concept
2.Applicable to elementary as well as
complex reactions.
2.Applicable to elementary reactions
only.
(b)
Rate = k[2X] [3Y]
Rate of the reaction will increase by six times
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CBSE Class 12 Chemistry past-paper question from the 2025 board exam, with the answer as CBSE’s own marking scheme gives it. Where our answers come from.