default_background
✕

Find the best tutors and institutes for Class 12 Tuition

Find Best Class 12 Tuition

Please select a Category.

Please select a Locality.

No matching category found.

No matching Locality found.

Q6.22(vi):
What happens when (vi) methyl chloride is treated with KCN?

Solution :

Step 1: Chemical Reaction Analysis

The reaction involves the interaction between an alkyl halide, specifically methyl chloride ($CH_3Cl$), and an inorganic cyanide source, potassium cyanide ($KCN$). Potassium cyanide is an ionic compound that dissociates in an aqueous alcoholic medium to yield $K^+$ and $CN^-$ ions.

The $CN^-$ ion acts as an ambident nucleophile, meaning it has two nucleophilic centers: the carbon atom and the nitrogen atom. However, in the case of $KCN$, the reaction proceeds via the carbon atom because the $C-C$ bond is significantly more thermodynamically stable than the $C-N$ bond.

Step 2: Mechanism of Nucleophilic Substitution ($S_N2$)

Since methyl chloride is a primary alkyl halide, the reaction proceeds via an $S_N2$ (Substitution Nucleophilic Bimolecular) mechanism. The reaction follows a single-step concerted pathway where the nucleophile attacks the electrophilic carbon from the backside while the chloride leaving group departs.

Chemical Equation:

$CH_3Cl + KCN \xrightarrow{\text{aqueous ethanol}} CH_3CN + KCl$

Step 3: Visual Representation of the Molecular Interaction

CH₃—Cl + K⁺—:C≡N⁻ CH₃—C≡N + KCl

Step 4: Product Characterization

The primary product formed is methyl cyanide (also known as acetonitrile or ethanenitrile). [Per IUPAC nomenclature, the carbon of the cyano group is included in the parent alkane chain].

Reactant Reagent Major Product By-product
$CH_3Cl$ $KCN$ $CH_3CN$ $KCl$

Step 5: Theoretical Justification

The preference for the formation of alkyl cyanides ($R-CN$) over alkyl isocyanides ($R-NC$) when using $KCN$ is governed by the ionic nature of the $K-CN$ bond. In an ionic salt, the cyanide ion has a higher electron density on the carbon atom, rendering it more nucleophilic than the nitrogen atom [Nucleophilic attack occurs at the site of highest electron density]. Conversely, if $AgCN$ (a covalent reagent) were used, the attack would occur via the nitrogen atom, yielding an isocyanide.

Final Solution: When methyl chloride is treated with KCN, it undergoes a nucleophilic substitution reaction to form methyl cyanide (acetonitrile) and potassium chloride.


More Questions from Class 12 Chemistry Haloalkanes and Haloarenes Exercises


CBSE Solutions for Class 12 Chemistry Haloalkanes and Haloarenes


Chapters in CBSE - Class 12 Chemistry


Top Tutors who teach Haloalkanes and Haloarenes

(22)
Top Tutor
locationImg Electronic City, Bangalore
experience 11 yrs of Exp students 5 students
greenClock 185 hrs of classes completed
rsIcon 500 per hour
Math & Science Teacher with 15 Years Experience
Online Classes Online Classes

Well experienced in physics and chemistry of XI , XII standard in both ICSE and CBSE curricular. Taken part time classes in college for ISC syllabus. Strong hold on Mechanics and Organic compounds and thermodynamics.

Skills: Physics
Also teaches: Class 11 Tuition, Class 6 Tuition and more

(6)
Top Tutor
locationImg Indian Institute of Technology Roorkee, Roorkee
experience 5 yrs of Exp students 1 student
greenClock 13 hrs of classes completed
rsIcon 600 per hour
I've been in academia since 2012 and PhD from IIT Roorkee.
Online Classes Online Classes
homeTutions Student's Home

I am working as an engineer and hold a PhD degree from IIT Roorkee. Last year, I successfully taught 6 students from this plateform.

MANJU pal

Explain the topic very well . Understand the needs of students. Gave sufficient time to student for proper learning and understanding the subject.

Skills: English , Mathematics and more

(8)
Top Tutor
locationImg Kuvempu Nagar, Bellary
experience 20 yrs of Exp students 3 students
greenClock 359 hrs of classes completed
rsIcon 400 per hour
Unlocking Math Potential – Guiding Students to Achieve Academic Excellence
Online Classes Online Classes
regularClasses Tutor's home

Teaching CBSE 12th Mathematics online and offline

Skills: Mathematics , Applied Mathematics
Also teaches: Vedic Maths Training, Class 10 Tuition and more

(33)
Top Tutor
locationImg Ambala, Ambala
experience 10 yrs of Exp students 4 students
greenClock 273 hrs of classes completed
rsIcon 185 per hour
Creating Confident And Independent Learning
Online Classes Online Classes

I am a History and law graduate, specializing in coaching students appearing for their board exams. From clearing concepts to teaching how to efficiently write answers, I do it all. For Class 12, I focus on: * Clear understanding of concepts, thinkers & case studies * Answer writing practice as per board requirements * Important questions, PYQs & expected topics * Smart revision techniques to improve scores My classes are one-on-one and tailored to your pace so that you feel confident before exams.

Ayaan

I had a great experience with Kanika Ma’am. She taught me political science for my boards. She is a very knowledgeable and kind teacher. Must recommend.

Skills: Political Science , History

(15)
Top Tutor
locationImg Malviya Nagar, Delhi
experience 20 yrs of Exp students 4 students
greenClock 255 hrs of classes completed
rsIcon 600 per hour
International Educator (English & French), Certified Expert-Teacher (from Planet Spark & Turito)
Online Classes Online Classes

I feel myself God-blessed, having been able to guide thousands of students/learners English, as a school subject as well as a language since 1992. I'm glad to notice that these learners have not only been doing well in their respective areas but also excelling in the real-life situations. May God bless them!!

Skills: English , French

Other Subjects in CBSE - Class 12

Worksheet Icon

Download free CBSE - Class 12 Chemistry Haloalkanes and Haloarenes Exercises worksheets

Download Now

Find Best Class 12 Tuition ?

Find Now »