Practice free Chemistry NEET multiple-choice questions online with instant answers and detailed explanations. No login required.
The time for half-life of a first order reaction is 1 hr. What is the time taken for 87.5% completion of the reaction?
(c) 87.5% completion means 3 half lives.
Which order of reaction obeys the relation t1/2 = 1/Ka?
(b) For II order reaction, t = (1/K){x/a(a-x)'}
if x = a/2, t1/2 = 1/K.a'
The chemical reaction, 2O3 3O2 proceeds as follows;
O3 O2 + O .....(Fast)
O+O3 2O2 ....(Slow)
The rate law expression should be:
(b) For slow step, rate = K[O3][O2] ... (i)
Also for equilibrium Kc=[O][O2] / [O3] .....(ii)
[O] = Kc[O3]/[O2] .. (iii)
By Eqs. (iii) and (i) the intermediate [O] is eliminated as rate = K.Kc[O3][O3]/[O2] = K'[O3]2 /[O2]
The rate of reaction becomes 2 times for every 10°C rise in temperature. How the rate of reaction will increase when temperature is increased from 30°C to 80°C?
(b) Kt+10/Kt =rt+10/rt = 2;
For an increase of temperature to 50°C, i.e, 5 times, the rate increases by 25 times, i.e, 32 times
The rate constant (K) for the reaction 2A +B Product was found to be 2.5x10-5 litre mol-1 sec-1 after 15 sec, 2.60 x10-5 litre mol-1sec-1 after 30 sec and 2.55 x10-5litre mol-1 sec-1 after 50 sec. The order of reaction is:
(a) K does not change with time; also unit of K suggest it to be II order
Now, r = k[A] = 10-2x0.1 = 102Msec-1
A reaction A2 + B2 2AB occurs by the following mechanism;
A2 A + A .....(slow)
A + B2 AB + B .....(fast)
A + B AB .....(fast)
Its order would be:
(b) rate = K[ A2]
For a given reaction, presence of catalyst reduces the energy of activation by 2 kcal at 27C. The rate of reaction will be increased by:
What fraction of a reactant showing first order remains after 40 minute if t1/2 is 20 minute?
N=N0/2n
n=T/tN1/2=40/20=2
N=N0/22=N0/4
Rate equation for a second order reaction is:
(c) dx/dt = K(a-x)2 is differential form of II order. Integrate it to get (c).
For the reaction 2NO2 + F2 → 2NO2F, following
mechanism has been provided,
NO2 + F2 NO2F+F
NO2 + F NO2F
Thus, rate expression of the above
reaction can be written as:
(b) Slowest step of mechanism decides the rate expression, thus, rate = K[NO2][F2]
Ready to ace NEET?
Free access · No credit card required
Yes. You can attempt every Chemistry question on this page for free without logging in, and check the correct answer with a detailed explanation instantly.
No account is required to attempt questions and view answers. A free account adds bookmarks, personal notes, and progress tracking.
The bank mixes NEET previous year questions (PYQs) with practice questions, each tagged with its exam appearances where applicable.