1
WB JEE 2021
MCQ (Single Correct Answer)
+1
-0.25
Under the same reaction conditions, initial concentration of 1.386 mol dm$$-$$3 of a substance becomes half in 40 s and 20 s through first-order and zero-order kinetics respectively. Ratio $$\left( {{{{k_1}} \over {{k_0}}}} \right)$$ of the rate constants for first-order (k1) and zero-order (k0) of the reactions is
A
0.5 mol$$-$$1 dm3
B
0.5 mol dm$$-$$3
C
1.0 mol dm3
D
2.0 mol$$-$$1 dm3
2
WB JEE 2021
MCQ (Single Correct Answer)
+1
-0.25
2.5 mL 0.4 M weak monoacidic base (Kb = 1 $$\times$$ 10$$-$$12 at 25$$^\circ$$C) is titrated with 2/15 M HCl in water at 25$$^\circ$$C. The concentration of H+ at equivalence point is (Kw = 1 $$\times$$ 10$$-$$14, at 25$$^\circ$$C)
A
3.7 $$\times$$ 10$$-$$13 M
B
3.2 $$\times$$ 10$$-$$7 M
C
3.2 $$\times$$ 10$$-$$2 M
D
2.7 $$\times$$ 10$$-$$2 M
3
WB JEE 2020
MCQ (Single Correct Answer)
+2
-0.5
For a reaction 2A + B $$ \to $$ P, when concentration of B alone is doubled, t1/2 does not change and when concentrations of both A and B is doubled, rate increases by a factor of 4. The unit of rate constant is,
A
s-1
B
L mol-1s-1
C
mol L-1s-1
D
L2mol-2s-1
4
WB JEE 2019
MCQ (Single Correct Answer)
+1
-0.33
Consider the following two first order reactions occurring at 298 K with same initial concentration of A :

(1) A $$\to$$ B; rate constant, k = 0.693 min$$-$$1

(2) A $$\to$$ C; half-life, t1/2 = 0.693 min

Choose the correct option.
A
Reaction (1) is faster than reaction (2)
B
Reaction (1) is slower than reaction (2)
C
Both reactions proceed at the same rate.
D
Since two different products are formed, rates cannot be compared.
WB JEE Subjects