1
NEET 2019
+4
-1
If the rate constant for a first order reaction is k, the time (t) required for the completion of 99 % of the reaction is given by :
A
$$t = {{4.606} \over k}$$
B
$$t = {{2.303} \over k}$$
C
$$t = {{0.693} \over k}$$
D
$$t = {{6.909} \over k}$$
2
NEET 2019
+4
-1
For the chemical reaction
N2(g) + 3H2(g) ⇌ 2NH3(g)
the correct option is :
A
$$- {{d\left[ {{N_2}} \right]} \over {dt}} = 2{{d\left[ {N{H_3}} \right]} \over {dt}}$$
B
$$- {{d\left[ {{N_2}} \right]} \over {dt}} = {1 \over 2}{{d\left[ {N{H_3}} \right]} \over {dt}}$$
C
$$3{{d\left[ {{H_2}} \right]} \over {dt}} = 2{{d\left[ {N{H_3}} \right]} \over {dt}}$$
D
$$- {1 \over 3}{{d\left[ {{H_2}} \right]} \over {dt}} = -{1 \over 2}{{d\left[ {N{H_3}} \right]} \over {dt}}$$
3
NEET 2018
+4
-1
The correct difference between first and second order reactions is that
A
the rate of a first-order reaction does not depend on reactant concentrations; the rate of a second-order reaction does depend on reactant concentrations
B
the half-life of a first-order reaction does not depend on [A]0 ; the half-life of a second order reaction does depend on [A]0
C
a first-order reaction can be catalysed; a second-order reaction cannot be catalysed
D
the rate of a first-order reaction does depend on reactant concentrations; the rate of a second-order reaction does not depend on reactant concentrations
4
NEET 2018
+4
-1
When initial concentration of the reactant is doubled, the half-life period of a zero order reaction
A
is halved
B
is doubled
C
is tripled
D
remains unchanged.
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