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Question
The rate law for a reaction of A, B and C has been found to be rate = `"k" ["A"]^2["B"] ["L"]^(3/2)`. How would the rate of reaction change when
- Concentration of [L] is quadrupled
- Concentration of both [A] and [B] are doubled
- Concentration of [A] is halved
- Concentration of [A] is reduced to `(1/3)` and concentration of [L] is quadrupled.
Solution
Rate = `"k" ["A"]^2["B"] ["L"]^(3/2)` ..........(1)
i. when [L] = [4L]
Rate = `"k" ["A"]^2["B"] [4"L"]^(3/2)`
Rate = `8 ("k" ["A"]^2["B"] ["L"]^(3/2))` ........(2)
Comparing (1) and (2); rate is increased by 8 times.
ii. when [A] = [2A] and [B] = [2B]
Rate = `"k" [2"A"]^2 [2"B"] ["L"]^(3/2)`
Rate = `8 ("k" ["A"]^2["B"] ["L"]^(3/2))` ........(3)
Comparing (1) and (3); rate is increased by 8 times.
iii. when [A] = `["A"/2]`
Rate = `"k" ["A"/2]^2 ["B"] ["L"]^(3/2)`
Rate = `(1/4) ("k" ["A"]^2["B"] ["L"]^(3/2))` .........(4)
Comparing (1) and (4); rate is reduced to `1/4` times.
iv. when [A] = `["A"/3]` and [L] = [4L]
Rate = `"k" ["A"/3]^2 ["B"] [4"L"]^(3/2)`
Rate = `(8/9) ("k" ["A"]^2["B"] ["L"]^(3/2))` ........(5)
Comparing (1) and (5); rate is reduced to `8/9` times.
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