Electrophilic Addition (ethene School) — Hbr and Steam
Unsymmetric alkene: two possible products; major follows Markovnikov named.
Learning objectives
- Define hbr and steam using accurate chemistry terms.
- Explain why hbr and steam matters within electrophilic addition (ethene school).
- Apply the learning unit to an FBISE-style example, comparison, diagram, or calculation.
Definition
Unsymmetric alkene: two possible products; major follows Markovnikov named. Ethene + H2O (acid) -> ethanol named. Cold dilute KMnO4: diol, purple fade (named mild ox). Mechanism arrows: pi electrons attack E+, then Nu- attacks carbocation. This page separates the idea from the wider topic “ELECTROPHILIC ADDITION (ETHENE SCHOOL)” so it can be revised and assessed on its own.
Formula
C=C alkane does not (no C
Important terms
- HBr AND STEAM
- Unsymmetric alkene: two possible products; major follows Markovnikov named.
- ELECTROPHILIC ADDITION (ETHENE SCHOOL)
- Ethene + Br2: the C=C attacks Br2, a bromonium / stepwise school picture, product 1,2-dibromoethane.
Overview
Study this learning unit in three steps:
Key Idea
Unsymmetric alkene: two possible products; major follows Markovnikov named. Ethene + H2O (acid) -> ethanol named. Cold dilute KMnO4: diol, purple fade (named mild ox). Mechanism arrows: pi electrons attack E+, then Nu- attacks carbocation.
Examples Propene + HBr named · Ethene hydration named · KMnO4 diol named
Exam Application
Exam Br2 test: alkene decolourises Br2 water addition across C=C alkane does not (no C=C)
Examples Propene + HBr named · Ethene hydration named · KMnO4 diol named
WHAT — ELECTROPHILIC ADDITION (ETHENE SCHOOL) — HBR AND STEAM
Unsymmetric alkene: two possible products; major follows Markovnikov named. Ethene + H2O (acid) -> ethanol named. Cold dilute KMnO4: diol, purple fade (named mild ox). Mechanism arrows: pi electrons attack E+, then Nu- attacks carbocation. This page separates the idea from the wider topic “ELECTROPHILIC ADDITION (ETHENE SCHOOL)” so it can be revised and assessed on its own.
WHY — Why this topic matters
ELECTROPHILIC ADDITION (ETHENE SCHOOL) — HBR AND STEAM 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
Unsymmetric alkene: two possible products; major follows Markovnikov named. Ethene + H2O (acid) -> ethanol named. Cold dilute KMnO4: diol, purple fade (named mild ox). Mechanism arrows: pi electrons attack E+, then Nu- attacks carbocation. Examples: Propene + HBr named; Ethene hydration named; KMnO4 diol named. Exam use: Exam Br2 test: alkene decolourises Br2 water addition across C=C alkane does not (no C=C)
Explanation
Unsymmetric alkene: two possible products; major follows Markovnikov named. Ethene + H2O (acid) -> ethanol named. Cold dilute KMnO4: diol, purple fade (named mild ox). Mechanism arrows: pi electrons attack E+, then Nu- attacks carbocation. Examples: Propene + HBr named; Ethene hydration named; KMnO4 diol named. Exam use: Exam Br2 test: alkene decolourises Br2 water addition across C=C alkane does not (no C=C)
In simple words
Federal Board Class 11 Chemistry learning unit. Easy wording; no provincial-board material added.
Key points
- H to richer H carbon
- orange disappears
Exam preparation
Exam Focus
Quick revision
Revision Zone
Electrophilic Addition (ethene School) — Hbr and Steam
Sticky Notes · Quick Revision
Core idea
- Unsymmetric alkene: two possible products; major follows Markovnikov named. Ethene + H2O (acid) -> ethanol named. Cold dilute KMnO4: diol, purple fade (named mild ox). Mechanism arrows: pi electrons attack E+, then Nu- attacks carbocation. This page separates the idea from the wider topic “ELECTROPHILIC ADDITION (ETHENE SCHOOL)” so it can be revised and assessed on its own.
WHAT
- Unsymmetric alkene: two possible products; major follows Markovnikov named.
WHY
- ELECTROPHILIC ADDITION (ETHENE SCHOOL) — HBR AND STEAM is an independent FBISE learning unit because students must use its definitions, conditions, equations, or trends separately in explanations and calculations.
HOW
- Unsymmetric alkene: two possible products; major follows Markovnikov named. Ethene + H2O (acid) -> ethanol named. Cold dilute KMnO4: diol, purple fade (named mild ox). Mechanism arrows: pi electrons attack E+, then Nu- attacks carbocation. Examples: Propene + HBr named; Ethene hydration named; KMnO4 diol named. Exam use: Exam Br2 test: alkene decolourises Br2 water addition across C=C alkane does not (no C=C)
Common misconception
- Do not treat hbr and steam as the same as every other part of electrophilic addition (ethene school); define this unit and use its own evidence, steps, or conditions.
FBISE exam check
- Define electrophilic addition (ethene school) — hbr and steam, explain how it works, and support the answer with one relevant example.
60-second revision
- Unsymmetric alkene: two possible products; major follows Markovnikov named.
- Propene + HBr named
- Exam link: H to richer H carbon.
Did you understand this topic?
Your answer is saved with your learning record. It does not mark the topic as mastered.