Growing the Chain (nitrile Named)

Growing the Chain (nitrile Named)

What is it?

Haloalkane + CN- (ethanolic KCN named in many books) -> nitrile, one extra carbon. Hydrolyse nitrile: carboxylic acid (acidic) or carboxylate (alkali). Reduce nitrile: amine (named hydride or H2). Meaning: C1 to C2 acid is a classic exam (bromomethane -> ethanenitrile -> ethanoic). Cyanide is toxic — named reagent, hazard slogan, not a student method to run, not a poison recipe. CN- substitution on halogenoalkane adds one carbon; nitrile reduced to amine or hydrolysed to acid. Count carbons after each synthetic step; silent carbon loss is the most common multi-step mistake.

In simple words

• Haloalkane + CN- (ethanolic KCN named in many books) -> nitrile, one extra carbon.
• 1. STEP-UP: Count carbons in the target acid.
• 2. HAZARD: Cyanide: poison slogan, specialist conditions, medical emergency if exposure.
• Exam reminder: Worked C1 to C2 acid: CH3Br + CN- -> CH3CN hydrolyse CH3CN -> CH3COOH named steps; cyanide hazard slogan, not a how-to

Important terms

GROWING THE CHAIN (NITRILE NAMED): Haloalkane + CN- (ethanolic KCN named in many books) -> nitrile, one extra carbon.

1. STEP-UP: Count carbons in the target acid.

2. HAZARD: Cyanide: poison slogan, specialist conditions, medical emergency if exposure.

What you should learn

• Explain growing the chain (nitrile named) in simple chemical language.
• Connect 1. step-up with 2. hazard using equations, observations, or trends where needed.
• Answer a short Federal Board question with the correct terms and a clear reason.

Examples

• KCN named
• Hydrolyse named
• Ethanoic from bromomethane

STEP-UP

Count carbons in the target acid. If one more than the haloalkane you have, use nitrile. Then hydrolyse. Draw both steps. Grignard adds R group to carbonyl — carbon count rises.

HAZARD

Cyanide: poison slogan, specialist conditions, medical emergency if exposure. These notes never describe how to generate HCN gas or to dose anyone. Exam: write KCN(eth) as the book does. Wittig named for alkene from carbonyl — optional name only.

Full school-level explanation

Haloalkane + CN- (ethanolic KCN named in many books) -> nitrile, one extra carbon. Hydrolyse nitrile: carboxylic acid (acidic) or carboxylate (alkali). Reduce nitrile: amine (named hydride or H2). Meaning: C1 to C2 acid is a classic exam (bromomethane -> ethanenitrile -> ethanoic). Cyanide is toxic — named reagent, hazard slogan, not a student method to run, not a poison recipe. CN- substitution on halogenoalkane adds one carbon; nitrile reduced to amine or hydrolysed to acid. Count carbons after each synthetic step; silent carbon loss is the most common multi-step mistake.

Why CN-, then the hazard:

WHAT — GROWING THE CHAIN (NITRILE NAMED)

Haloalkane + CN- (ethanolic KCN named in many books) -> nitrile, one extra carbon. Hydrolyse nitrile: carboxylic acid (acidic) or carboxylate (alkali). Reduce nitrile: amine (named hydride or H2). Meaning: C1 to C2 acid is a classic exam (bromomethane -> ethanenitrile -> ethanoic). Cyanide is toxic — named reagent, hazard slogan, not a student method to run, not a poison recipe. CN- substitution on halogenoalkane adds one carbon; nitrile reduced to amine or hydrolysed to acid. Count carbons after each synthetic step; silent carbon loss is the most common multi-step mistake.

WHY — Why this topic matters

GROWING THE CHAIN (NITRILE NAMED) is an independent FBISE learning unit because students must use its definitions, conditions, equations, or trends separately in explanations and calculations.

HOW — How it works

STEP-UP: Count carbons in the target acid. If one more than the haloalkane you have, use nitrile. Then hydrolyse. Draw both steps. Grignard adds R group to carbonyl — carbon count rises. Examples: KCN named; Hydrolyse named; Ethanoic from bromomethane. HAZARD: Cyanide: poison slogan, specialist conditions, medical emergency if exposure. These notes never describe how to generate HCN gas or to dose anyone. Exam: write KCN(eth) as the book does. Wittig named for alkene from carbonyl — optional name only. Examples: Toxic slogan; Not a method; Hospital if exposure. Worked C1 to C2 acid: CH3Br + CN- -> CH3CN hydrolyse CH3CN -> CH3COOH named steps; cyanide hazard slogan, not a how-to

STEP-UP

Count carbons in the target acid. If one more than the haloalkane you have, use nitrile. Then hydrolyse. Draw both steps. Grignard adds R group to carbonyl — carbon count rises.

Remember

• +1 carbon

Examples

• KCN named
• Hydrolyse named
• Ethanoic from bromomethane

HAZARD

Cyanide: poison slogan, specialist conditions, medical emergency if exposure. These notes never describe how to generate HCN gas or to dose anyone. Exam: write KCN(eth) as the book does. Wittig named for alkene from carbonyl — optional name only.

Remember

• name + warning

Examples

• Toxic slogan
• Not a method
• Hospital if exposure

Remember

• CN- adds one carbon
• then hydrolyse to acid
• +1 carbon
• names + warning
• +1 carbon
• name + warning
• CN- adds one carbon
• then hydrolyse to acid

How the ideas connect

Worked C1 to C2 acid: CH3Br + CN- -> CH3CN hydrolyse CH3CN -> CH3COOH named steps; cyanide hazard slogan, not a how-to

Deeper understanding

Go beyond memorising Growing the Chain (nitrile Named). Connect the definition to reasons, relationships, exceptions, and exam wording.

How the ideas connect

Worked C1 to C2 acid: CH3Br + CN- -> CH3CN hydrolyse CH3CN -> CH3COOH named steps; cyanide hazard slogan, not a how-to

Common mistakes

Exam focus

Core Idea

1. STEP-UP

2. HAZARD

Exam Example

Exam focus

Quick revision

• CN- adds one carbon
• then hydrolyse to acid
• +1 carbon
• names + warning
• GROWING THE CHAIN (NITRILE NAMED): Haloalkane + CN- (ethanolic KCN named in many books) -> nitrile, one extra carbon.
• 1. STEP-UP: Count carbons in the target acid.

Named step-up. No cyanide how-to, no poisons.

For long answers on Growing the Chain (nitrile Named): define clearly → explain the main parts → give one example → state one exam caution.