The Question is from neet-chemistry hydrocarbons , and it was created by the author Mr. S M HUSSAIN

Question

Which statement is FALSE regarding the chlorination of 2,2,4-trimethylpentane at 300 K?

Mr. S M HUSSAIN · Accepted Answer

## CORE INFORMATION
✓ **Answer**: C
## CONCEPT FRAMEWORK
	**Primary Concept**: Free Radical Halogenation of Alkanes
	**Related Topics**: Relative reactivity of C-H bonds, Regioselectivity, Radical chain reaction mechanism
	**Prerequisites**: Alkane structure and nomenclature, Reaction mechanisms
## SOLUTION PATHWAY
**Given Information**:
	Chlorination of 2,2,4-trimethylpentane at 300 K.
**Method & Steps**:
	1. Analyze the structure of 2,2,4-trimethylpentane and identify the different types of hydrogens (primary, secondary, tertiary).
	Reasoning:  The reactivity of C-H bonds in free radical halogenation follows the order: tertiary > secondary > primary.
	2. Consider the relative reactivity of different C-H bonds and predict the major product(s).
	Working:  2,2,4-trimethylpentane has primary, secondary, and tertiary hydrogens. The tertiary C-H bond is the most reactive.
	Key Point:  While the tertiary hydrogen is most reactive, there is only one tertiary hydrogen in the molecule. There are considerably more primary hydrogens.
	3. Evaluate the truthfulness of each option based on the mechanism and expected product distribution.
	Result: Option C is false. Although the tertiary hydrogen is more reactive, it is outnumbered by the primary hydrogens. Statistically, 1-chloro-2,2,4-trimethylpentane will be the major product.
	Verification:  The relative reactivity of tertiary to primary hydrogens is approximately 5:1 at 300 K.  Considering the number of each type of hydrogen, monochlorination at the primary position will be statistically favored.
## OPTION ANALYSIS
[A] ✓: True. Tertiary hydrogens are significantly more reactive than primary hydrogens in free radical chlorination due to the increased stability of the tertiary radical intermediate.
[B] ✓: True.  Chlorination of alkanes proceeds through a radical chain mechanism involving initiation, propagation, and termination steps.
[C] :x: False. While the tertiary hydrogen is more reactive on a per-hydrogen basis, the sheer number of primary hydrogens (9 primary vs 1 tertiary) leads to the primary chlorination product being major. 1-chloro-2,2,4-trimethylpentane will be the major product.
[D] ✓: True. Multiple monochlorinated products can form because there are different types of hydrogens present in the molecule, leading to chlorination at different positions.
## LEARNING AIDS
	**Common Mistakes**:
		1. Focusing only on relative reactivity and ignoring the number of each type of hydrogen: Always consider both reactivity and the number of hydrogens available when predicting the major product.
		2. Assuming only one product forms: Free radical halogenation often leads to a mixture of products.
	**Quick Tips**:
		1. Remember the relative reactivity order: tertiary > secondary > primary.
		2. Consider statistical factors: The number of each type of hydrogen influences the product distribution.

Mr. S M HUSSAIN · Answer

The relative reactivity of tertiary hydrogens compared to primary hydrogens is greater than 1.

Mr. S M HUSSAIN · Answer

The reaction proceeds via a radical mechanism.

Mr. S M HUSSAIN · Answer

The correct Option is "The tertiary hydrogen is chlorinated preferentially, yielding 4-chloro-2,2,4-trimethylpentane as the major product."

Mr. S M HUSSAIN · Answer

Multiple monochlorinated products are formed.

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