Activation Energy and its Calculation NEET Questions

Physical Chemistry - Chemical Kinetics

Activation Energy and its Calculation MCQ Questions


13.
The relationship between activation energies of forward (Ef) and backward (Eb) reactions and enthalpy change (ΔH) is:
A.
ΔH = Ef − Eb
B.
ΔH = Eb − Ef
C.
ΔH = Ef + Eb
D.
ΔH = Ef × Eb
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ANSWER :
A. ΔH = Ef − Eb
14.
A catalyst increases the rate of reaction by:
A.
Increasing the temperature
B.
Lowering the activation energy of the reaction
C.
Increasing the concentration of reactants
D.
Increasing the activation energy
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ANSWER :
B. Lowering the activation energy of the reaction
15.
If the activation energy of a reaction is 50 kJ/mol and temperature is increased from 27°C to 37°C, the ratio k₂/k₁ is approximately (R = 8.314 J/mol/K):
A.
≈ 1
B.
≈ 4
C.
≈ 0.5
D.
≈ 2
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ANSWER :
D. ≈ 2
16.
The Arrhenius plot (ln k vs 1/T) for a reaction is found to have a slope of −1×10⁴ K. The activation energy of the reaction is (R = 8.314 J/mol/K):
A.
0.8314 kJ/mol
B.
8.314 kJ/mol
C.
831.4 kJ/mol
D.
83.14 kJ/mol
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ANSWER :
D. 83.14 kJ/mol
17.
The intercept of Arrhenius plot (ln k vs 1/T) on the y-axis equals:
A.
ln k₀
B.
−ln A
C.
ln A
D.
−Ea/R
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ANSWER :
C. ln A
18.
If the activation energy of a reaction is high, the reaction:
A.
Is always fast
B.
Is independent of temperature
C.
Is slow at room temperature but speeds up significantly with temperature
D.
Has zero rate at any temperature
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ANSWER :
C. Is slow at room temperature but speeds up significantly with temperature