
Which of the following reactions has zero activation energy?
A) $C{H_4} + Cl \cdot \to \cdot C{H_3} + HCl$
B) $C{l_2} \to 2Cl \cdot $
C) \[ \cdot C{H_3} + \cdot C{H_3} \to C{H_3} - C{H_3}\]
D) \[ \cdot C{H_3} + Cl - Cl \to C{H_3} + Cl + Cl \cdot \]
Answer
476.4k+ views
Hint: The activation energy is defined as the energy that must be provided to compounds so that they result in a chemical reaction. Activation energy can be thought of as the magnitude of the potential barrier (sometimes called the energy barrier) separating minima of the potential energy surface pertaining to the initial and final thermodynamic state.
Complete step by step answer:
The reactions that favor forming products on their own are said to have zero activation energy.
Among the given four reactions only one reaction will have zero activation energy. The reaction is:
\[ \cdot C{H_3} + \cdot C{H_3} \to C{H_3} - C{H_3}\]
This is so because the reactants in the reaction consist of highly reactive free methyl radicals which are so energetic that they react very rapidly as soon as another free radical is introduced to it.
All the other reactions mentioned above are following a free radical mechanism which requires energy in the form U.V radiation which has very high activation energy.
In the above reaction, the free radicals (which are unstable due to the presence of high energy) are bonded together and thus, lower their energy by increasing the stability.
Thus, the correct option is C.
Note:
The activation energy is defined as the energy required converting the inactive reactant into their excited states such that their activity increases and they form the corresponding product. When this energy is zero, it means that either the reaction is too feasible that it takes place without any external push or energy; or it also means that the solution in which the reactant takes place consists of highly reactive reaction intermediates.
Complete step by step answer:
The reactions that favor forming products on their own are said to have zero activation energy.
Among the given four reactions only one reaction will have zero activation energy. The reaction is:
\[ \cdot C{H_3} + \cdot C{H_3} \to C{H_3} - C{H_3}\]
This is so because the reactants in the reaction consist of highly reactive free methyl radicals which are so energetic that they react very rapidly as soon as another free radical is introduced to it.
All the other reactions mentioned above are following a free radical mechanism which requires energy in the form U.V radiation which has very high activation energy.
In the above reaction, the free radicals (which are unstable due to the presence of high energy) are bonded together and thus, lower their energy by increasing the stability.
Thus, the correct option is C.
Note:
The activation energy is defined as the energy required converting the inactive reactant into their excited states such that their activity increases and they form the corresponding product. When this energy is zero, it means that either the reaction is too feasible that it takes place without any external push or energy; or it also means that the solution in which the reactant takes place consists of highly reactive reaction intermediates.
Recently Updated Pages
Master Class 12 Economics: Engaging Questions & Answers for Success

Master Class 12 Maths: Engaging Questions & Answers for Success

Master Class 12 Biology: Engaging Questions & Answers for Success

Master Class 12 Physics: Engaging Questions & Answers for Success

Master Class 12 Business Studies: Engaging Questions & Answers for Success

Master Class 12 English: Engaging Questions & Answers for Success

Trending doubts
Which are the Top 10 Largest Countries of the World?

Differentiate between homogeneous and heterogeneous class 12 chemistry CBSE

What is a transformer Explain the principle construction class 12 physics CBSE

Draw a labelled sketch of the human eye class 12 physics CBSE

What are the major means of transport Explain each class 12 social science CBSE

How much time does it take to bleed after eating p class 12 biology CBSE
