Question detail
What is the general formula for alkanes?
Try the question, check the answer, then read the explanation to understand the curriculum point.
At a glance
MCQ
Type
practice
Style
Topic
Carbon compounds as fuels and feedstock
Question
- A. CnH2n
- B. CnH2n+2
- C. CnH2n-2
- D. CnH2n+1
Answer
The correct option is CnH2n+2.
Explanation
The correct option is CnH2n+2. CnH2n+2 is correct because it directly supports the approved learning objective to recall how boiling point changes with increasing molecular size. This belongs to Properties and combustion of hydrocarbons within Carbon compounds as fuels and feedstock, so the answer must use the correct organic chemistry context. The other options are incorrect when they confuse the organic family, formula type, reaction condition, product, or property being tested. Keep molecular formula, structural formula, displayed formula, and general formula distinct. Do not confuse alkanes with alkenes, saturated with unsaturated, cracking with combustion, polymers with monomers, or hydrocarbons with oxygen-containing alcohols and carboxylic acids. When formulae are used, preserve the stored notation exactly and explain the GCSE chemistry idea in words rather than using unsupported displayed-formula diagrams.
Common mistake
Boiling point misconception
Students think larger hydrocarbons have lower boiling points because they are lighter
Explain that larger hydrocarbons have higher boiling points due to increased London dispersion forces, which grow with molecular size and surface area
Related flashcards
Flashcard 1 of 5
Related practice questions
Question 1 of 5
Choose an answer, get feedback, then move sideways through the set.