NEETChemistryChemical Kinetics
Match List-I with List-II for a first-order reaction: List-I (Percentage completion) List-II (Time required) (A) 75 % (I) 10 t_ 1/2 (B) 87.5 % (II) 3.32 t_ 1/2 (C) 90 % (III) 2 t_ 1/2 (D) 99.9 % (IV) 3 t_ 1/2 Choose the correct answer from the options given below:
Options
- A(A)-(II), (B)-(IV), (C)-(III), (D)-(I)
- B(A)-(III), (B)-(IV), (C)-(I), (D)-(II)
- C(A)-(IV), (B)-(III), (C)-(II), (D)-(I)
- D(A)-(III), (B)-(IV), (C)-(II), (D)-(I)
Correct answer
D. (A)-(III), (B)-(IV), (C)-(II), (D)-(I)
Step-by-step solution
For a first-order reaction, the time required for completion is given by t = 2.303 k 100 100-x . For 75 % completion: t_ 75 % = 2.303 k 100 25 = 2.303 k 4 = 2 2.303 2 k = 2 t_ 1/2 . For 87.5 % completion: t_ 87.5 % = 2.303 k 100 12.5 = 2.303 k 8 = 3 2.303 2 k = 3 t_ 1/2 . For 90 % completion: t_ 90 % = 2.303 k 100 10 = 2.303 k 10 . Since t_ 1/2 = 2.303 0.3010 k , we have t_ 90 % = t_ 1/2 0.3010 3.32 t_ 1/2 . For 99.9 % completion: t_ 99.9 % = 2.303 k 100 0.1 = 2.303 k 1000 = 3 2.303 k 3 3.32 t_ 1/2 10 t_ 1/2 . Thus