Haloalkanes And Haloarenes Practice Quiz - 1 - Class 9 MCQ

Its IUPAC name is 2-iodo-2-methyl propane.

CHCl₃ on reaction with oxygen forms phosgene.

Aromaticity condition involves huckel rule (4n+2) Pie electrons. And proper delocalization of pie electron.

This is intramolecular wurtz reaction.

R—X is polar.

Boron cannot expand its covalency due to absence of d orbitals.

NaNH₂ is very strong base it will abstract H from alkyne and then substitution reaction will occur.

Allylic position is 1 carbon after double bonded carbon.

this is not chiral.

This is example of electrophilic aromatic substitution (EAS)

Intramolecular wurtz leading to cyclisaion.

Answer:
The reaction RX 2Na RX → R – R 2NaX is called the Wurtz-Fittig reaction. Here is a detailed explanation:
1. Wurtz-Fittig Reaction:
- The Wurtz-Fittig reaction is a type of organic synthesis reaction.
- It involves the coupling of two alkyl or aryl halides in the presence of sodium metal (2Na) to form a carbon-carbon bond and produce a symmetrical alkyl or aryl compound.
- The reaction is named after Charles Adolphe Wurtz and Emil Fischer Fittig, who independently discovered and developed this reaction.
2. Reaction Mechanism:
- In the Wurtz-Fittig reaction, two molecules of alkyl or aryl halides (RX) are treated with sodium metal (2Na).
- The sodium metal acts as a reducing agent and generates sodium radicals (Na•) by losing an electron.
- The sodium radicals then react with the alkyl or aryl halides to form sodium alkyl or aryl radicals (R•).
- Finally, the sodium alkyl or aryl radicals combine with each other to form a symmetrical alkyl or aryl compound (R - R) along with the formation of sodium halide (2NaX) as a byproduct.
3. Application and Significance:
- The Wurtz-Fittig reaction is widely used in organic synthesis to prepare symmetrical alkyl or aryl compounds.
- It is particularly useful for the synthesis of hydrocarbons, such as alkanes, alkenes, and alkynes.
- The reaction provides a straightforward and efficient method for the formation of carbon-carbon bonds.
- However, it is important to note that the Wurtz-Fittig reaction is not suitable for the synthesis of unsymmetrical compounds.
Therefore, the correct answer is D. Wurtz-Fittig reaction.

For a mixture of two enantiomers , one rotates the plane polarized light towards left and other towards right therefore there is no optical rotation and hence mixture is optically inactive.

DDT is a pesticide.

this is the original compound.

Pent-2-ene is major product as ore substituted alkene is formed in major quantity according to zaitsev rule.

CCl₄ is degreasing agent.

Longest chain will be of three carbon to which Cl and CH₃ will be attached at 2 position.

To draw the structures of the given compounds, we need to follow the rules of IUPAC nomenclature and assign appropriate substituents to the parent chain.
(i) 4-tert. Butyl-3-iodoheptane:
- The parent chain contains 7 carbons, so the base name is heptane.
- The substituents are 4-tert. butyl and 3-iodo.
- The structure of 4-tert. butyl is a branched chain with a tert-butyl group attached to the fourth carbon of the parent chain.
- The structure of 3-iodo is a halogen group attached to the third carbon of the parent chain.
- Combine the parent chain and substituents to draw the structure.
(ii) 1,4-Dibromobut-2-ene:
- The parent chain contains 4 carbons, so the base name is butene.
- The substituents are 1,4-dibromo and 2-ene.
- The structure of 1,4-dibromo is two bromine atoms attached to the first and fourth carbons of the parent chain.
- The structure of 2-ene is a double bond between the second and third carbons of the parent chain.
- Combine the parent chain and substituents to draw the structure.
Answer: The structure given in option A is the correct structure for both compounds.

Due to {sp²} hybridisation of C-atom in chlorobenzene, C-atom is more electronegative
(greater s-character) whereas in cyclohexyl chloride,C-atom is sp hybridised, i.e. less electronegative
(lesser s-character). So, polarity of C—Cl bond in chlorobenzene is less than the C—Cl bond in cyclohexyl chloride. Further, due to delocalisation of lone pair of electrons of Cl-atom over the benzene ring, C—Cl bond in chlorobenzene acquires some double bond character while C—Cl bond in cyclohexyl chloride is a pure single bond. Thus, C—Cl bond in chlorobenzene is shorter than in cyclohexyl chloride. As dipole moment is a product of charge and distance, therefore, the dipole moment of chlorobenzene is lower than that of cyclohexyl chloride.

CHI₃ is antiseptic drug.

CH₃NH₂ can act as nucleophile to cause substitution reaction. (CH₃)₄N⁺ this is formed when 3 moles of CH₃NH₂ reacts with methyl halide.

Vanderwall forces increases with increase in molecular mass and boiling point increases with vanderwall forces..