For each pair of substrates below, choose the one that will react faster in a substitution reaction, assuming that: 1. the rate law for the substitution reaction has a first-order dependence on the concentration of the alkyl halide, and 2. doesn't depend on the concentration of the other reactant at all. Substrate A JI..... Br Br Substrate B CI CO*** Br Faster Rate (Choose one) (Choose one) (Choose one) X
Reactive Intermediates
In chemistry, reactive intermediates are termed as short-lived, highly reactive atoms with high energy. They rapidly transform into stable particles during a chemical reaction. In specific cases, by means of matrix isolation and at low-temperature reactive intermediates can be isolated.
Hydride Shift
A hydride shift is a rearrangement of a hydrogen atom in a carbocation that occurs to make the molecule more stable. In organic chemistry, rearrangement of the carbocation is very easily seen. This rearrangement can be because of the movement of a carbocation to attain stability in the compound. Such structural reorganization movement is called a shift within molecules. After the shifting of carbocation over the different carbon then they form structural isomers of the previous existing molecule.
Vinylic Carbocation
A carbocation where the positive charge is on the alkene carbon is known as the vinyl carbocation or vinyl cation. The empirical formula for vinyl cation is C2H3+. In the vinyl carbocation, the positive charge is on the carbon atom with the double bond therefore it is sp hybridized. It is known to be a part of various reactions, for example, electrophilic addition of alkynes and solvolysis as well. It plays the role of a reactive intermediate in these reactions.
Cycloheptatrienyl Cation
It is an aromatic carbocation having a general formula, [C7 H7]+. It is also known as the aromatic tropylium ion. Its name is derived from the molecule tropine, which is a seven membered carbon atom ring. Cycloheptatriene or tropylidene was first synthesized from tropine.
Stability of Vinyl Carbocation
Carbocations are positively charged carbon atoms. It is also known as a carbonium ion.
![**Substitution Reactions: Predicting the Effect of Carbocation Stability on the Reaction Rate**
For each pair of substrates below, choose the one that will react faster in a substitution reaction, assuming that:
1. The rate law for the substitution reaction has a first-order dependence on the concentration of the alkyl halide, and
2. It doesn't depend on the concentration of the other reactant at all.
**Substrates:**
1. **Pair 1:**
- **Substrate A:** Contains a chloride ion (Cl) attached to a secondary carbon.
- **Substrate B:** Contains a bromide ion (Br) attached to a tertiary carbon with additional branching.
- **Faster Rate Selection:** [Dropdown menu to choose Substrate A or B]
2. **Pair 2:**
- **Substrate A:** Contains a bromide ion (Br) attached to a benzyl position with additional methyl substitution.
- **Substrate B:** Contains a chloride ion (Cl) attached to a benzyl position with methyl substitution.
- **Faster Rate Selection:** [Dropdown menu to choose Substrate A or B]
**Explanation and Check:**
Buttons are provided for explanation and to check the selection.
(Note: This information is for educational purposes and is based on structure-reactivity relationships in organic chemistry. Benzyl and tertiary carbocations generally have higher stability, leading to faster substitution reactions.)](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F593e4a4c-a9fc-4231-bacd-fbc9affb1612%2Fd727670b-6ac4-4c8f-b9db-936344708efc%2Fl9ux5p8_processed.jpeg&w=3840&q=75)
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