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Class 12 Haloalkanes and Haloarenes worksheet
CBSE Chemistry. Naming and classes, SN1 and SN2, elimination, Wurtz and other named reactions, boiling points. Every sheet has 20 questions in three sections and an answer key, and the numbers change every time.
Sample questions
Real questions from this chapter, as the app sets them. Tap Answer to see the answer and working.
Section A · multiple choice
- 1.
The C–X bond in haloalkanes is polar because:
- both atoms have equal electronegativity
- the bond is ionic
- carbon is more electronegative
- the halogen is more electronegative than carbon
Answer
(d) the halogen is more electronegative than carbon
- 2.
The IUPAC name of (CH₃)₂CHI is:
- 2-iodopropane
- 2-iodobutane
- 2-iodo-2-methylpropane
- 1-iodobutane
Answer
(a) 2-iodopropane
common name: isopropyl iodide
- 3.
2-chloropropane ((CH₃)₂CHCl) is a:
- tertiary (3°) alkyl halide
- primary (1°) alkyl halide
- vinylic halide
- secondary (2°) alkyl halide
Answer
(d) secondary (2°) alkyl halide
count the carbons attached to the carbon bearing the halogen
Section B · short answer
- 4.
Why are haloalkanes only slightly soluble in water, though they are polar?
Answer
To dissolve, energy is needed to break the hydrogen bonds between water molecules, and haloalkanes cannot form hydrogen bonds with water to release as much energy.
- 5.
Give the IUPAC name and the common name of CH₃CH₂Br, and classify it as primary, secondary or tertiary.
Answer
bromoethane; ethyl bromide; primary (1°)
count the carbons on the C–X carbon
Section C · long answer
- 6.
Explain the SN2 mechanism with an example, and say how the structure of the halide affects its rate.
Answer
In SN2 the nucleophile attacks the carbon from the side opposite the leaving group in one step through a five-coordinate transition state; the configuration is inverted. E.g. CH₃Cl + OH⁻ → CH₃OH + Cl⁻, rate = k[CH₃Cl][OH⁻]. Bulky groups block the backside, so the order is CH₃X > 1° > 2° > 3°.
Fresh sheets for your child
In the app, every Haloalkanes and Haloarenes sheet is new: the app remembers the questions your child has already had and leaves them out. Print the sheet as a PDF, or use notebook mode and write the answers in a notebook.
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