Match the entries of column I with appropriate entries of column II and choose the correct option out of the four options given.
| Column I | Column II |
| (a) Arrhenius equation | (i) Hp + (Ea)b |
| (b) Number of molecules undergoing effective collisions per unit time | (ii) k = Ae-Ea/RT |
| (c) Activation energy | (iii) \(\frac{k}{A}\) = e-Ea/RT |
| (d) Threshold energy | (iv) Ea |
Answer & explanation
Correct answer: option 4
The correct answer is option 4. (a)-(ii), (b)-(iii), (c)-(iv), (d)-(i).
| Column I | Column II |
| (a) Arrhenius equation | (i) Hp + (Ea)b |
| (b) Number of molecules undergoing effective collisions per unit time | (ii) k = Ae-Ea/RT |
| (c) Activation energy | (iii) \(\frac{k}{A}\) = e-Ea/RT |
| (d) Threshold energy | (iv) Ea |
Let us explain each of the matches between Column I and Column II in detail:
(a) Arrhenius Equation
This is a fundamental equation in chemical kinetics that describes how the rate constant (\( k \)) of a reaction depends on temperature (\( T \)) and activation energy (\( Ea \)).
\( k = Ae^{-Ea/RT} \)
\( k \)= Rate constant
\( A \) = Pre-exponential factor (frequency factor)
\( Ea \) = Activation energy
\( R \) = Gas constant
\( T \) = Temperature in Kelvin
So, Arrhenius equation corresponds to \( k = Ae^{-Ea/RT} \). Hence, (a) - (ii).
(b) Number of Molecules Undergoing Effective Collisions Per Unit Time
This term refers to the concept in the Arrhenius equation related to the frequency factor \( A \). The frequency factor \( A \) represents the number of collisions per unit time that are sufficiently energetic and correctly oriented to lead to a reaction.
The term \( kA = e^{-Ea/RT} \) seems to describe the frequency factor in relation to the Arrhenius equation, so (b) matches with (iii).
(c) Activation Energy
This is the minimum energy required for a reaction to occur. It represents the energy barrier that reactants must overcome to form products. The activation energy itself is denoted by \( Ea \). Therefore, (c) - (iv) is correct.
(d) Threshold Energy
This term is essentially synonymous with activation energy. It represents the minimum amount of energy required for a reaction to proceed. The term \(H_p + (E_a)_b\) might be less standard, but in this context, it appears to refer to the threshold or activation energy. This might be a specific format used in some texts, but the idea is consistent with activation energy. (d) corresponds to (i), which represents the activation energy in a specific format.