The resistance of 0.2 M solution of an electrolyte is 50 Ω. The specific conductance of the solution of 0.5 M solution of the same electrolyte is 1.4 S m^{-1} and resistance of the same solution of the same electrolyte is 280 Ω. The molar conductivity of 0.5 M solution of the electrolyte in Sm^{-2} mol^{-1} is
5 x 10^{-4}
5 x 10^{-3}
5 x 10^{3}
5 x 10^{2}
A.
5 x 10^{-4}
For first solution,
k = 1.4 Sm^{-1}, R =50 Ω , M =0.2
specific conductance
Two reactions R_{1} and R_{2} have identical pre-exponential factors. Activation energy of R_{1} exceeds that of R_{2} by 10 kJ mol^{–1}. If k_{1} and k_{2} are rate constants for reactions R_{1} and R_{2} respectively at 300 K, then ln(k_{2}/k_{1}) is equal to-
(R = 8.314 J mol^{–1}K^{–1})
8
12
6
4
D.
4
From Arrhenius equation
The rate of a chemical reaction doubles for every 10ºC rise of temperature. If the temperature is raised by 50ºC, the rate of the reaction increases by about
10 times
24 times
32 times
64 times
C.
32 times
For every 10^{o} C rise of temperature, the rate is doubled. Thus, temperature coefficient of the reaction = 2 when temperature is increased by 50^{o} rate becomes
Higher order (>3) reactions are rare due to:
the increase in entropy and activation energy as more molecules are involved.
shifting of equilibrium towards reactants due to elastic collisions
loss of active species on a collision
low probability of simultaneous collision of all the reacting species
A.
the increase in entropy and activation energy as more molecules are involved.
Conditions for the occurrence of a reaction:
(i) Proper orientation and effective collision of the reactants.
(ii) the chances of simultaneous collision with proper orientation between more than 3 species are very rare, so reaction with order greater than 3 are rare.
Decomposition of H_{2}O_{2} follows a first order reaction. In fifty minutes the concentration of H_{2}O_{2} decreases from 0.5 to 0.125 M in one such decomposition. When the concentration of H_{2}O_{2} reaches 0.05 M, the rate of formation of O_{2} will be:
6.93×10^{−4} mol min^{−1}
2.66 L min^{−1} at STP
1.34×10^{−2} mol min^{−1}
6.93×10^{−2} mol min^{−1}
A.
6.93×10^{−4} mol min^{−1}
The rate of a reaction doubles when its temperature changes from 300K to 310K. Activation energy of such a reaction will be (R = 8.314 JK^{–1} mol–1 and log 2 = 0.301)
53.6 kJ mol^{-1}
48.6 kJ mol^{-1}
58.5 kJ mol^{-1}
60.5 kJ mol^{-1}
A.
53.6 kJ mol^{-1}
By using Arrhenius equation,
Given, T2 = 310; T1 = 300K
On putting values in Eq (i), we get
For a first order reaction, (A) → products, the concentration of A changes from 0.1 M to 0.025 M in 40 minutes. The rate of reaction when the concentration of A is 0.01 M is
1.73 x 10^{–5} M/ min
3.47 x 10^{–4} M/min
3.47 x 10^{–5} M/min
1.73 x 10^{–4} M/min
B.
3.47 x 10^{–4} M/min
By first order kinetic rate constant,
Rate law for the reaction, A+ B → product is rate = k[A]^{2}[B] What is the rate constant; if rate of reaction at a given temperature is 0.22 Ms^{-1}, when [A]= 1 M band [BJ= 0.25 M?
3.52 M^{-2}s^{-1}
0.88 M^{-2}s^{-1}
1.136 M^{-2}s^{-1}
0.05 M^{-2}s^{-1}
B.
0.88 M^{-2}s^{-1}
$\mathrm{For}\mathrm{reaction};\mathrm{A}+\mathrm{B}\to \mathrm{product}\phantom{\rule{0ex}{0ex}}\frac{\mathrm{dx}}{\mathrm{dt}}=\mathrm{k}\left[\mathrm{A}{]}^{2}\right[\mathrm{B}]\Rightarrow 0.22=\mathrm{k}(1{)}^{2}(0.25)\phantom{\rule{0ex}{0ex}}\therefore \mathrm{k}=\frac{0.22}{0.25}=0.88{\mathrm{M}}^{-2}{\mathrm{s}}^{-1}$
The time for half life period of a certain reaction A → Products is 1 hour. When the initial concentration of the reactant ‘A’ is 2.0 mol L^{–1}, how much time does it take for its concentration to come from 0.50 to 0.25 mol L^{–1} if it is a zero order reaction?
1 h
4 h
0.25 h
0.5 h
C.
0.25 h
Given that [A]_{o} = 2 mol L^{-1}
For the non- stoichiometric reaction 2A + B → C + D, the following kinetic data were obtained in three separate experiment, all at 298 K.
Initial concentration (A) | Initial concnetration (B) | Initial rate of formation of C (mol L^{-1} S^{-1}) | |
1 | 0.1 M | 0.1 M | 1.2 x 10^{-3} |
2 | 0.1 M | 0.2 M | 1.2 x 10^{-3} |
3 | 0.2 M | 0.1 M | 2.4 x 10^{-3} |
D.