Alkynes MCQ Quiz in मल्याळम - Objective Question with Answer for Alkynes - സൗജന്യ PDF ഡൗൺലോഡ് ചെയ്യുക

The correct option is one sigma and two pi bonds.

Key Points

•  The alkynes are composed of one sigma and two pi bonds.
• Alkynes are hydrocarbon compounds containing triple bonds.
• The general formula for an alkyne is CnH2n-2.
• Alkyne contains two Carbon and two hydrogen atoms attached with triple bonds.
• The IUPAC name for alkynes is written by using the suffix -yne.
• For example C₂H₂ Ethyne.

Additional Information

•  A Sigma bond is formed between atomic orbitals due to head-to-head overlapping.
• Pi bonds are formed between sidewise positive overlapping of atomic orbitals.
• The Sigma bond is a strong bond.
• A pi bond is quite a weak bond and can be broken easily.
• Sigma bond is formed by s-s, s-p, and p-p overlapping of atomic orbitals.

The correct answer is Ethyne.

Key Points

• A homologous series is a collection of compounds that have similar chemical properties and functional groups.
• The general formula for alkynes is CnH2n2, where n is the number of carbon atoms.
• Ethyne is the first member of the alkyne homologous series.
• Ethene is the first member of the alkene homologous series.
• Methane is the first member of the alkane homologous series.

The correct answer is Ethyne.

Key Points

• A homologous series is a collection of compounds that have similar chemical properties and functional groups.
• The general formula for alkynes is CnH2n2, where n is the number of carbon atoms.
• Ethyne is the first member of the alkyne homologous series.
• Ethene is the first member of the alkene homologous series.
• Methane is the first member of the alkane homologous series.

The correct answer is Ethyne.

Key Points

• A homologous series is a collection of compounds that have similar chemical properties and functional groups.
• The general formula for alkynes is CnH2n2, where n is the number of carbon atoms.
• Ethyne is the first member of the alkyne homologous series.
• Ethene is the first member of the alkene homologous series.
• Methane is the first member of the alkane homologous series.

The correct option is Alkynes.

Key Points

• The 'sp' hybridization is present in alkynes.
• Alkynes contain triple bonds.
• The C-C bonds overlap to form a sigma bond.
• One 's' and one 'p' orbital of carbon atom overlap and form an 'sp' hybrid orbital in alkynes.
• Thus it shows a linear shape and geometry.

Additional Information Alkanes

• Alkanes contain 'sp³' hybridization.
• It shows a tetrahedral shape and geometry.

Alkenes

• Alkenes contain 'sp2'  hybridization.
• It shows a trigonal planar shape and geometry.

Cycloalkanes

• Cycloalkanes contain single bonds.
• They have 'sp3' hybridization.
• Thus it shows tetrahedral shape and geometry.

Concept:

Electrolysis-

• It is a type of reaction where chemical decomposition occurs.
• This is done by passing an electric current through a liquid containing ions.
• Anions travel to the anode and get oxidized.
• Cations travel to the cathode and get reduced.

​Kolbe's Electrolytic Reaction:

• An aqueous solution of sodium or potassium salt of a saturated monocarboxylic acid yields alkanes on Electrolysis.

Steps of the reaction-

​At anode:

• The first involves homolytic cleavage of the R--COOH bond of the carboxylic acids.
• Free radical R. of the alkyl group is formed.
• The reaction proceeds via the formation of free radicals.
• A new C-C bond is formed between two alkyl groups by the combination of their free radicals R·.
• CO2  is formed as a byproduct.

​At cathode:

• NaOH is formed.
• Hydrogen is liberated.

The general form of the reaction is-

Explanation:

• When salts of dicarboxylic acids are taken, alkenes and alkynes are formed.
• When Potassium succinate is taken, ethylene is formed.
• When a salt of fumaric acid is taken, acetylene is formed.

The reaction at the anode:

Acetylene is formed.

Reaction at cathode:

2K + 2e^- → 2K + H₂O → KOH.

Hence, acetylene is obtained by the electrolysis of sodium fumarate.

Important Points

• Sodium or potassium maleate is the geometrical isomer of fumarate and yields acetylene.

Key Points

• The general molecular formula for alkynes is Cn H2n - 2
• Alkynes are hydrocarbons that contain at least one carbon-carbon triple bond.
• This triple bond gives alkynes distinct properties compared to alkanes and alkenes.
• Alkynes are unsaturated hydrocarbons, meaning they have fewer hydrogen atoms than alkanes.
• The simplest alkyne is ethyne, also known as acetylene, with the formula C2 H2

Additional Information

• Alkynes are more reactive than alkanes due to the presence of the triple bond.
• They are used in various industrial applications, including welding and the synthesis of organic compounds.
• Alkynes can undergo a variety of chemical reactions, such as hydrogenation, halogenation, and polymerization.

The correct answer is MeO - CH2 - Cl.

Key Points

• MeO-CH2- Cl will react faster in an SN1 reaction with the OH- ion.
  • This happens due to the stability of the carbocation in the compound.

Additional Information

• The SN1 mechanism involves the formation of a carbocation intermediate in the rate-determining step.
• The most stable carbocation will produce the fastest reaction.
• The SN​1, reaction proceeds in two steps.
  • Involves slow separation of halogen to form carbonium ion.
  • Involves the attack of the nucleophile on carbonium ion from both sides to form alcohol.
• The reactivity of alkyl halides towards SN1 reactions decreases in the same order, i.e. 3° alkyl halides > 2° alkyl halides > 1° alkyl halides > methyl halides.

The correct answer is MeO - CH2 - Cl.

Key Points

• MeO-CH2- Cl will react faster in an SN1 reaction with the OH- ion.
  • This happens due to the stability of the carbocation in the compound.

Additional Information

• The SN1 mechanism involves the formation of a carbocation intermediate in the rate-determining step.
• The most stable carbocation will produce the fastest reaction.
• The SN​1, reaction proceeds in two steps.
  • Involves slow separation of halogen to form carbonium ion.
  • Involves the attack of the nucleophile on carbonium ion from both sides to form alcohol.
• The reactivity of alkyl halides towards SN1 reactions decreases in the same order, i.e. 3° alkyl halides > 2° alkyl halides > 1° alkyl halides > methyl halides.

The correct answer is MeO - CH2 - Cl.

Key Points

• MeO-CH2- Cl will react faster in an SN1 reaction with the OH- ion.
  • This happens due to the stability of the carbocation in the compound.

Additional Information

• The SN1 mechanism involves the formation of a carbocation intermediate in the rate-determining step.
• The most stable carbocation will produce the fastest reaction.
• The SN​1, reaction proceeds in two steps.
  • Involves slow separation of halogen to form carbonium ion.
  • Involves the attack of the nucleophile on carbonium ion from both sides to form alcohol.
• The reactivity of alkyl halides towards SN1 reactions decreases in the same order, i.e. 3° alkyl halides > 2° alkyl halides > 1° alkyl halides > methyl halides.