Free Alkynes MCQs with Answers

• A. 1, 5 - Hexadiyne - 3 - ene
• B. 1, 5 - Hexadiene 3 - yne
• C. 3 - Hexene - 1,5 - diyne
• D. 3 - Hexyne - 1 , 5 - diene

Explanation: This is consistent with option B. Note: - is used to separate words from numbers.

• A. Addition reaction
• B. Elimination reaction
• C. Substitution reaction
• D. Halogenation

Explanation: Alkynes undergo addition reactions across the triple bond because of their weak pi-bonds between carbon atoms, which are converted into…

• A. Acidic
• B. Basic
• C. Neutral
• D. None

Explanation: Alkynes are slightly acidic in nature due to the presence of a hydrogen atom attached to a highly electronegative carbon-carbon triple…

• A. Propanal
• B. Propyl hydrogen sulfate
• C. Acetone
• D. Propanol

Explanation: When propyne is treated with acidified HgSO4, the major product formed is acetone (Propanone).

• A. Acetic acid
• B. Ethyl alcohol
• C. Oxalic acid
• D. Ethylene glycol

Explanation: The end product of the oxidation of ethyne is Oxalic acid. When ethyne undergoes oxidation, it first forms Glyoxal, which then further…

• A. O2
• B. Br2
• C. NaNH2
• D. HCl

Explanation: The correct answer is Option C: NaNH2. 1-Butyne and 2-butyne can be differentiated using NaNH2 due to the reactivity of terminal hydrogen.

• A. Ethane
• B. Ethene
• C. Ethyne
• D. Methane

Explanation: Option A is incorrect as Alkanes have the highest bond length (of about 1.54 Angstrom).

• A. Ethene
• B. Ethane
• C. Ethyne
• D. Methane

Explanation: The bond length for a given pair of elements is a function of number and types of orbital overlaps.

• A. Polyvinyl polymer
• B. Polyvinyl Acetylene
• C. Neoprene
• D. Chloroprene

Explanation: The reaction of vinyl acetylene with HCl produces chloroprene. Chloroprene is a synthetic rubber that is used in a variety of…

• A. 2500°C
• B. 2600°C
• C. 2700°C
• D. 2800 °C

Explanation: When lime is heated with coke at about 2800°C in an electric furnace, calcium carbide is produced, which on hydrolysis yields acetylene.

• A. Ethylene
• B. Acetylene
• C. Acetone
• D. Ethene

Explanation: The first member of the Alkyne series is Ethyne which is also known as Acetylene in the common naming, having the formula C2H2.

• A. Red
• B. White
• C. Brown
• D. Pinkish

Explanation: Silver, in the form of Ag+, despite being a transition element, forms colourless compounds.

• A. Methane
• B. Ethane
• C. Propane
• D. Acetylene

Explanation: Carbide of alkaline earth metals are decomposed by water to form acetylene (C2H2). E.g: CaC2+ 2H2O ------ Ca(OH)2+ C2H2

• A. Benzene
• B. 1,3,5-cyclohexatriene
• C. Hexene
• D. Butane

Explanation: This option is correct since polymer is formed by combination of monomers.At 873 K when acetylene is passed through a red hot iron tube…

• A. Ozonolysis
• B. Hydroxylation
• C. Acetylide formation
• D. Kolbe's electrolysis

Explanation: Acetylene (C2H2) possesses two hydrogen atoms bonded to carbon atoms in its structure that exhibit acidic properties.

• A. 1
• B. 3
• C. 4
• D. 2

Explanation: Acetylene, C2H2, can be converted to ethane, C2H6, by a process known as hydrogenation.

• A. Benzene
• B. Ethane
• C. Ethene
• D. Ethyne

Explanation: Ethyne, also known as acetylene, is the most reactive among the given options due to its triple bond between the carbon atoms.

• A. CH4
• B. C2H2
• C. C2H4
• D. C2H6

Explanation: Metallic carbide/Calcium Carbide: CaC2 Calcium carbide on hydration gives acetylene.

• A. C2H6
• B. C2H4
• C. C2H2
• D. C6H6

Explanation: Only alkynes can perform this reaction. 2[Cu(NH)3]OH + HC≡CH → Cu−C≡C−Cu + 4NH3 + 2H2O copper acetylide Red ppt.

• A. Br2 in organic solvent
• B. Baeyer's reagent
• C. Phenyl Hydrazine
• D. Tollen's reagent

Explanation: The correct answer is Tollen's reagent. Ethene does not react with Tollen's reagent, whereas Ethyne reacts with it to form a white…