Alkynes (Acetylenes) questions

The compound whose molecular formula is C₄H₆ has the general formula ..........

1. A CₙH₂ₙ₊₂
2. B CₙH₂ₙ₋₂
3. C CₙH₂ₙ
4. D CₙH₂ₙ₊₁

The homologous series that starts with acetylene includes a compound whose molar mass is .......... [C = 12 , H = 1]

1. A 44 g/mol
2. B 40 g/mol
3. C 56 g/mol
4. D 58 g/mol

The chemical formulas of the following compounds follow the general formula of alkynes, except ..........

1. A A
2. B B
3. C C
4. D D

What is the number of sigma bonds in one molecule of a branched alkyne with the molecular formula C₇H₁₂?

1. A 14
2. B 16
3. C 18
4. D 20

What is the number of carbon atoms in the simplest branched alkyne molecule?

1. A 3
2. B 4
3. C 5
4. D 6

What is the IUPAC name of the opposite compound?
CH₃–CH₂–C≡C–CH₃

1. A 3-pentyne.
2. B 1-methyl-1-butyne.
3. C 2-pentyne.
4. D 1,3-dimethyl-1-propyne.

What is the IUPAC name of the opposite compound?

1. A 4-methyl-4-bromo-2-pentyne.
2. B 4-bromo-4-methyl-2-pentyne.
3. C 2-bromo-2-methyl-3-pentyne.
4. D 2-methyl-2-bromo-3-pentyne.

What is the IUPAC name of the compound CH₃(CH₂)₂C₂CH₃?

1. A 2-hexene.
2. B 4-hexyne.
3. C 2-hexyne.
4. D 4-hexene.

What is the IUPAC name of the opposite compound?

1. A 4-propyl-2-pentyne.
2. B 4-methyl-5-heptyne.
3. C 2-propyl-3-pentyne.
4. D 4-methyl-2-heptyne.

What is the IUPAC name of the compound HCCC(CH₃)₃?

1. A 2,2-dimethyl-2-butyne.
2. B 2,2-dimethyl-3-pentyne.
3. C 3,3-dimethyl-1-butyne.
4. D 1-hexyne.

What is the IUPAC name of the compound CH₃CH(C₂H₅)C₂H?

1. A 1-hexyne.
2. B 3-methyl-1-pentyne.
3. C 2-ethyl-2-butyne.
4. D 4-ethyl-1-butyne.

Which of the following is a correct name according to the IUPAC system?

1. A 2-methyl-4-pentyne.
2. B 2-methyl-3-butyne.
3. C 4-ethyl-2-heptyne.
4. D 5-ethyl-2-hexyne.

What is the IUPAC name of dimethylacetylene?

1. A 1-butyne.
2. B 2-butyne.
3. C 1-methylpropyne.
4. D 1,2-dimethylethyne.

Which of the following expresses the number of hydrogen atoms and the number of methyl groups in one molecule of 4-methyl-2-pentyne?

1. A number of H atoms : 10 , number of (CH₃–) groups : 3
2. B number of H atoms : 10 , number of (CH₃–) groups : 1
3. C number of H atoms : 9 , number of (CH₃–) groups : 3
4. D number of H atoms : 9 , number of (CH₃–) groups : 1

Which of the following compounds contains a methylene group?

1. A Propyne.
2. B 1-butyne.
3. C 2-butyne.
4. D 4,4-dimethyl-2-pentyne.

What is the number of branched isomers of an alkyne with a molecular mass of 82 g/mol? [C = 12 , H = 1]

1. A 2
2. B 3
3. C 4
4. D 5

What is the number of open-chain isomers for the molecular formula C₃H₂ClBr?

1. A 2
2. B 3
3. C 4
4. D 5

Which of the following contains the largest number of hydrogen atoms?

1. A 0.1 mol of pentane.
2. B 0.2 mol of 2-butene.
3. C 0.1 mol of propyne.
4. D 0.5 mol of hydrogen.

Which of the following expresses the substance used to prepare ethyne and propyne by hydrolysis?

1. A ethyne : CaC₂ , propyne : CaC₂
2. B ethyne : Mg₂C₃ , propyne : Mg₂C₃
3. C ethyne : CaC₂ , propyne : Mg₂C₃
4. D ethyne : Mg₂C₃ , propyne : CaC₂

What is the volume of the gas produced (at STP) when 6.43 g of water reacts completely with excess calcium carbide? [H₂O = 18 g/mol]

1. A 4 L
2. B 8 L
3. C 36 L
4. D 72 L

What is the number of moles of ethyne gas that can be obtained from 9 mol of methane gas?

1. A 18 mol
2. B 9 mol
3. C 4.5 mol
4. D 2.25 mol

From the opposite chart:
All of the following are correct, except ..........

1. A In process (1), COONa is replaced by a hydrogen atom.
2. B Compound (A) is used to obtain carbon black.
3. C Compound (B) follows the general formula CₙH₂ₙ₋₂
4. D Process (2) takes place at 1000°C in the absence of air.

From the opposite chart:
Which of the following is correct?

1. A (1) : fractional distillation , (A) : unsaturated , (B) : saturated.
2. B (1) : dry distillation , (A) : saturated , (B) : unsaturated.
3. C (2) : fractional distillation , (A) : saturated , (B) : unsaturated.
4. D (2) : dry distillation , (A) : unsaturated , (B) : saturated.

Which of the following hydrocarbons is the most chemically active?

1. A C₂H₆
2. B C₂H₂
3. C C₂H₄
4. D CH₄

All of the following are properties of ethyne gas, except that it ..........

1. A does not dissolve in water.
2. B is flammable.
3. C is a saturated compound.
4. D has no isomers.

When acetylene burns in the air, .......... is/are produced.

1. A CO₂(g) , H₂O(v)
2. B CO(g) , H₂O(v)
3. C C(s) , CO(g) , H₂O(v)
4. D C(s) , CO₂(g) , H₂O(v)

The number of moles of oxygen needed for the complete combustion of one mole of alkynes equals .......... (where n is the number of carbon atoms in the alkyne molecule)

1. A (n − 1)
2. B (3n − 1)/2
3. C (n + 1)
4. D (3n + 1)/2

The number of moles of water vapour produced by burning one mole of an alkyne equals .......... (where n is the number of carbon atoms in the alkyne molecule)

1. A n
2. B (n + 1)
3. C 2n
4. D (n − 1)

400 g of ethyne gas are burned. Half the amount burns completely and the other half burns incompletely.
What is the mass of the gases and vapours produced by the two combustion processes? [C₂H₂ = 26 g/mol , CO₂ = 44 g/mol , H₂O = 18 g/mol]

1. A 0.93 kg
2. B 1.29 kg
3. C 1.55 kg
4. D 2.5 kg

What is the number of moles of gases and vapours in a closed container after the complete combustion of a mixture of 1 mol of ethyne with 4 mol of oxygen?

1. A 3 mol
2. B 4.5 mol
3. C 5.5 mol
4. D 6 mol

1 mol of an organic compound burns completely using 2.5 mol of O₂ gas
What is this organic compound?

1. A C₂H₅OH only.
2. B C₂H₅OH or C₂H₂
3. C C₂H₂ only.
4. D C₂H₂ or CH₃CHO

The complete combustion reaction of ethyne is used in ..........

1. A welding metals.
2. B obtaining carbon black.
3. C preparing methane.
4. D condensation polymerization.

The flame used to cut metals is produced by the complete reaction of a number of moles of the oxidizing gas (X) with a volume of gas (Y).
Which of the following expresses the number of moles of gas (X) and the volume of gas (Y) (at STP)?

1. A (X) : 2 mol , (Y) : 17.92 L
2. B (X) : 2 mol , (Y) : 100 L
3. C (X) : 5 mol , (Y) : 60.12 L
4. D (X) : 5 mol , (Y) : 250 L

Which gases must be present for the rusting and the welding of iron?

1. A rusting of iron : oxygen , nitrogen / welding of iron : oxygen , ethyne
2. B rusting of iron : oxygen , nitrogen / welding of iron : air , ethyne
3. C rusting of iron : oxygen , water vapour / welding of iron : oxygen , ethyne
4. D rusting of iron : oxygen , water vapour / welding of iron : air , ethyne

What is the name of the compound produced by the complete hydrogenation of 2-butyne?

1. A 1,2-dimethylethene.
2. B 1,2-dimethylethane.
3. C 2-butene.
4. D butane.

When a number of moles of hydrogen is added to an equal number of moles of an alkyne, .......... is formed.

1. A an alkane
2. B an alkene
3. C an aldehyde
4. D an alcohol

What is the mass of calcium carbide needed to prepare 14 g of ethene? [Ca = 40 , C = 12 , H = 1]

1. A 1.6 g
2. B 3.2 g
3. C 34.46 g
4. D 32 g

The following three reactions show the steps for preparing polyethene from calcium carbide:
(1) CaC₂ + 2H₂O → Ca(OH)₂ + C₂H₂
(2) C₂H₂ + H₂ → C₂H₄
(3) nC₂H₄ → –[CH₂–CH₂]ₙ–
What mass of the polymer can be obtained from 64 kg of CaC₂? [Ca = 40 , C = 12 , H = 1]

1. A 7 kg
2. B 14 kg
3. C 21 kg
4. D 28 kg

1 mol of compound (X) reacts with 2 mol of hydrogen gas to form 1 mol of compound (Y).
Which of the following expresses each of compounds (X) and (Y)?

1. A (X) : 4-methyl-1-hexyne , (Y) : 4-methylhexane.
2. B (X) : 4-chloro-2-pentyne , (Y) : 2-chloropentene.
3. C (X) : 4-chloro-2-pentyne , (Y) : 4-chloropentane.
4. D (X) : 4-methyl-1-hexyne , (Y) : 3-methylhexane.

Which of the following expresses the similarity (similarities) between 1-butyne and 2-butyne?

1. A general formula ✗ , flammability ✗ , reaction with H₂ ✓ , number of methylene groups ✓
2. B general formula ✓ , flammability ✓ , reaction with H₂ ✓ , number of methylene groups ✗
3. C general formula ✓ , flammability ✗ , reaction with H₂ ✗ , number of methylene groups ✗
4. D general formula ✗ , flammability ✓ , reaction with H₂ ✗ , number of methylene groups ✓

All of the following may decolourize bromine dissolved in carbon tetrachloride, except ..........

1. A the monomer of PE
2. B marsh gas.
3. C propyne.
4. D vinyl chloride.

Which pair of the following non-cyclic compounds can be distinguished using bromine dissolved in CCl₄?

1. A C₃H₈ , C₂H₆
2. B C₅H₈ , C₄H₆
3. C C₄H₈ , C₅H₁₀
4. D C₄H₁₀ , C₆H₁₀

When the carbide of a metal is treated with water, a gas is formed. When this gas is passed through bromine dissolved in CCl₄ , the colour of bromine disappears.
What is the name of this gas?

1. A Methane.
2. B Ethane.
3. C Acetylene.
4. D Ethylene.

When 1 mol of propyne reacts with 2 mol of a halogen, a compound is formed whose molecule contains all of the following, except ..........

1. A 4 halogen atoms.
2. B 2 methyl groups.
3. C 3 carbon atoms.
4. D 4 (C – H) bonds.

What is the number of moles of bromine dissolved in CCl₄ needed to distinguish between 1 mol of propene gas and 1 mol of propyne gas when each reacts separately?

1. A 1 mol
2. B 2 mol
3. C 3 mol
4. D 4 mol

HBr reacts with an alkyne of molar mass 40 g/mol to form compound (X).
Which of the following is correct? [C = 12 , H = 1]

1. A number of moles of HBr : 1 mol , compound (X) : 1-bromo-1-propene
2. B number of moles of HBr : 1 mol , compound (X) : 3-bromo-1-propene
3. C number of moles of HBr : 2 mol , compound (X) : 2,2-dibromopropane
4. D number of moles of HBr : 2 mol , compound (X) : 1,2-dibromopropane

Alkynes react with hydrogen halides in two steps.
Which of the following expresses the alkyne and the products of its reaction with hydrogen bromide?

1. A alkyne : 3-hexyne , first-step product : 3-bromo-3-hexene , second-step product : 4,4-dibromohexane
2. B alkyne : 1-hexyne , first-step product : 1-bromo-1-hexene , second-step product : 1,1-dibromohexane
3. C alkyne : 3-hexyne , first-step product : 3-bromo-4-hexene , second-step product : 3,3-dibromohexane
4. D alkyne : 1-hexyne , first-step product : 2-bromo-1-hexene , second-step product : 2,2-dibromohexane

Substance (X) reacts with a compound (Y) whose molecular formula is C₆H₁₀ to form the opposite compound (Z): CH₃(CH₂)₂CClCHCH₃
Which of the following expresses each of compounds (X) , (Y) , (Z)?

1. A (X) : Cl₂ , (Y) : 2-hexyne , (Z) : 4-chloro-5-hexene.
2. B (X) : HCl , (Y) : 1-hexyne , (Z) : 3-chloro-2-hexene.
3. C (X) : Cl₂ , (Y) : 1-hexyne , (Z) : 4-chloro-5-hexene.
4. D (X) : HCl , (Y) : 2-hexyne , (Z) : 3-chloro-2-hexene.

The following figure shows the apparatus used to prepare gas (X), which reacts with each of:
• H₂ gas, forming gas (Y).
• HBr gas, forming liquid (Z).
Which of the following expresses each of (X) , (Y) , (Z)?

1. A (X) : ethyne , (Y) : ethane , (Z) : 1,1,2,2-tetrabromoethane
2. B (X) : ethene , (Y) : ethyne , (Z) : 2-bromoethene
3. C (X) : ethyne , (Y) : ethane , (Z) : 1,1-dibromoethane
4. D (X) : ethene , (Y) : ethyne , (Z) : 1,1-dibromoethane

From the opposite chart:
All of the following are correct, except ..........

1. A (1) : calcium carbide , (3) : the simplest hydrocarbon.
2. B (2) : follows the formula (CₙH₂ₙ₋₂) , (4) : a reducing agent.
3. C (1) : decolourizes red bromine , (3) : chemically active.
4. D (2) : reacts with a hydrogen halide , (4) : an inorganic compound.

From the opposite chart: which of the following indicates each of compounds (1) , (2) , (3)?

1. A (1) : HC≡C(CH₂)₂CH₃ , (2) : H₃C(CH₂)₃CH₃ , (3) : CH₂Br(CH₂)₃CH₃
2. B (1) : HCCCH₂CH₂CH₃ , (2) : H₂CCH(CH₂)₂CH₃ , (3) : CH₂Br(CH₂)₃CH₃
3. C (1) : H₂CCHCH₂CH₂CH₃ , (2) : H₃C(CH₂)₃CH₃ , (3) : CH₃CH₂Br(CH₂)₂CH₃
4. D (1) : HC≡C(CH₂)₂CH₃ , (2) : H₂CCH(CH₂)₂CH₃ , (3) : CH₃CHBr(CH₂)₂CH₃

Which of the following reactions produces 2,2-dibromopropane?

1. A CH₂BrC≡CH + 2HBr →
2. B CH₃C≡CH + 2HBr →
3. C CH₃CH=CH₂ + HBr →
4. D CH₃CH=CHBr + HBr →

Which of the following is used to prepare the monomer of the polymer PVC?

1. A ethylene , HCl , H₂O
2. B calcium carbide , HCl , H₂O
3. C methane , HCl , H₂O
4. D ethanal , HCl , H₂O

Which of the following is needed when water is added to an alkyne?

1. A An acidic medium only.
2. B HgSO₄ + a base
3. C A neutral medium only.
4. D HgSO₄ + an acid

Four organic compounds:
• ethene. • ethanol. • ethanal. • ethanoic acid.
How many of them contain an odd number of sigma (σ) bonds?

1. A 1
2. B 2
3. C 3
4. D 4

What chemical processes are needed to convert ethanal into the monomer of the substance used to make plastic films and bags?

1. A hydrogenation – substitution – thermal decomposition.
2. B thermal decomposition – hydrogenation – substitution.
3. C reduction – replacement – thermal decomposition.
4. D replacement – thermal decomposition – reduction.

When acidified KMnO₄ solution reacts with CH₃(CH₂)₅CHO , .......... is formed.

1. A CH₃(CH₂)₅COOH
2. B CH₃(CH₂)₅CH₂OH
3. C CH₃(CH₂)₄COCH₃
4. D C₄H₉OC₃H₇

An aliphatic hydrocarbon (A) has a molar mass less than the molar mass of the simplest olefin by (2 g).
What chemical processes are needed to obtain ethanoic acid from compound (A)?

1. A Hydrogenation, then treatment with acidified KMnO₄(aq).
2. B Hydrogenation, then reduction.
3. C Catalytic hydration, then treatment with acidified KMnO₄(aq).
4. D Catalytic hydration, then reduction.

(X) and (Y) are two compounds:
• Compound (X): a symmetrical alkyne that contains 4 carbon atoms.
• Compound (Y): an alkyne that contains 3 carbon atoms.
(1) Draw the structural formula of compound (X).
(2) What is observed when 3 mol of bromine dissolved in CCl₄ is added to 1 mol of compound (Y)? Explain.

Write the IUPAC name of each of the following:

Draw the possible structural formulas of the open-chain alkyne isomers for the following molecular formulas:
(1) C₄H₆
(2) C₅H₈

A compound was named wrongly: 4-hexyne.
(1) What is the reason for this wrong name?
(2) What is the correct IUPAC name of this compound?

Curves (X) and (Y) shown in the opposite graph represent two homologous series of open-chain hydrocarbons.
State the name of each of them, and explain your answer.

An alkyne has a molar mass of 54 g/mol:
(1) Deduce its molecular formula.
(2) Draw its possible structural formulas.
[C = 12 , H = 1]

Write the chemical equations for adding 2 mol of HCl gas to 1 mol of ethyne gas, then halogenating the product using 4 mol of Cl₂ gas

Show by chemical equations how you can obtain ethane from calcium carbide.

Show by chemical equations how you can obtain ethanal from the smallest saturated hydrocarbon.

Compound (A) has the chemical formula CH₃CCCH₃ :
(1) How many moles of hydrogen are needed to convert compound (A) into a saturated compound?
(2) Write the IUPAC name of compound (B) produced by adding 2 mol of HBr to 1 mol of compound (A).

The following two compounds are unsaturated aliphatic hydrocarbons:
The first compound: CH₂=CH–C≡CH
The second compound: H₃C–CH₂–C≡CH
(1) Calculate the number of sigma bonds and pi bonds in the first compound.
(2) How many moles of hydrogen are needed to convert the second compound into a saturated compound?

From the following chart:
(1) Write the structural formula of each of: (a) compound (A). (b) compound (B).
(2) State the reaction condition in: (a) step (1). (b) step (2).

Three hydrocarbons (A , B , C): (Sample exam 2026)
(A) : a gas, one of the components of butagas, found in a smaller percentage in hot countries.
(B) : contains the same number of carbon atoms as compound (A), and its molecular formula has two hydrogen atoms fewer than compound (A).
(C) : unsaturated, and its molecular formula has two hydrogen atoms fewer than compound (B).
Which of the following expresses the products of complete hydrogenation, in the presence of a catalyst, of each of the above compounds?

1. A hydrogenation product of (A) : propane , hydrogenation product of (B) : propane , hydrogenation product of (C) : propane
2. B hydrogenation product of (A) : butane , hydrogenation product of (B) : propane , hydrogenation product of (C) : propene
3. C hydrogenation product of (A) : butane , hydrogenation product of (B) : cyclopropane , hydrogenation product of (C) : propyne
4. D hydrogenation product of (A) : propane , hydrogenation product of (B) : propene , hydrogenation product of (C) : propyne

Each of the following is correct for the chemical formula and the IUPAC name, except .......... (Sample exam 2026)

1. A (CH₃)₃CC(CH₃)₃ : 2,2,3,3-tetramethylbutane
2. B (CH₃)₂CC(CH₃)₂ : 2,3-dimethyl-2-butene
3. C (CH₃)₃CC(C₂H₅)₃ : 3,3-diethyl-2,2-dimethylpentane
4. D (CH₃)₃CCH₂C₂H : 4,4-dimethyl-2-butene

The correct name of the opposite compound according to the IUPAC system is .......... (Sample exam 2026)

1. A 2,4-dimethyl-1-pentyne.
2. B 3-propyl-1-butene.
3. C 2-ethyl-1-butene.
4. D 3-methyl-1-hexyne.

Which of the following expresses the correct order of some organic compounds according to the amount of oxygen needed to burn one mole of each completely? (Sample exam 2026)

1. A methane > ethane > ethene.
2. B ethane > ethene > ethyne.
3. C ethyne > ethene > ethane.
4. D ethyne > ethene > methane.

Which of the following is the name of one of the compounds produced when an ethyl group is bonded to the simplest branched alkyne? (1st session 2025)

1. A 2-methyl-3-hexyne.
2. B 2-methyl-1-pentyne.
3. C 4-methyl-1-hexyne.
4. D 3-methyl-1-pentyne.

(A) , (B) , (C) are three hydrocarbons. When HBr is added to each of them separately: (2nd session 2024)
(A) : gives 1,1-dibromoethane. (B) : gives bromoethane. (C) : does not react.
Which of the following choices expresses these compounds?

1. A (B) : ethene , (C) : ethyne.
2. B (A) : ethane , (B) : ethene.
3. C (C) : ethene , (B) : ethane.
4. D (A) : ethyne , (C) : ethane.

The following reactions take place under suitable conditions for compounds (X) and (Y), as shown in the chart: (1st session 2022)
(X) → (HBr) (Y) → (hydration) (Z)
Compound (Z) is ..........

1. A ethyne bromide.
2. B ethyl bromide.
3. C 1-bromoethanol.
4. D vinyl bromide.

The number of isomers of an alkyne made of three carbon atoms, a bromine atom and a chlorine atom equals .......... (Trial exam / March 2023)

1. A 5
2. B 2
3. C 4
4. D 3

(X) , (Y) , (Z) are three open-chain hydrocarbons. If: (Trial exam / May 2021)
(X) : reacts by addition in two stages.
(Y) : all its bonds are strong sigma bonds.
(Z) : decolourizes potassium permanganate solution in an alkaline medium.
Which of the following choices correctly expresses compounds (X , Y , Z)?

1. A X : alkyne , Y : alkane , Z : alkene
2. B X : alkene , Y : alkyne , Z : alkane
3. C X : alkane , Y : alkene , Z : alkyne
4. D X : alkene , Y : alkane , Z : alkyne

When 2 mol of red bromine solution dissolved in carbon tetrachloride are added to 1 mol of each of the compounds (2-butyne , pentane , 2-hexene), the correct choice for what happens to the colour of the solution is .......... (Trial exam / May 2021)

1. A 2-butyne : stays the same , pentane : stays the same , 2-hexene : stays the same
2. B 2-butyne : the colour disappears , pentane : stays the same , 2-hexene : stays the same
3. C 2-butyne : stays the same , pentane : stays the same , 2-hexene : the colour disappears
4. D 2-butyne : stays the same , pentane : the colour disappears , 2-hexene : stays the same

The correct IUPAC name of the opposite compound is .......... (1st session 2024)

1. A 3-methyl-1-pentene.
2. B 3-ethyl-1-pentyne.
3. C 3-methylpentane.
4. D 3-ethyl-1-pentene.

0.5 mol of a hydrocarbon reacts with 1 mol of bromine dissolved in carbon tetrachloride, so the formula of the product is .......... (Trial exam / June 2021)

1. A CₙH₂ₙ₋₂Br₄
2. B CₙH₂ₙ₋₂Br₂
3. C CₙH₂ₙBr₄
4. D CₙH₂ₙBr₂

The opposite table shows the molecular formulas of substances (X) and (Y). One mole of bromine dissolved in carbon tetrachloride is added to one mole of each of substances (X) and (Y) separately. (1st session 2021)
(X) : C₂H₂Br₂ , (Y) : C₄H₆
Which of the following is correct?

1. A The colour of bromine disappears with (X) and does not disappear with (Y).
2. B The colour of bromine does not disappear with (X) or with (Y).
3. C The colour of bromine disappears with (X) and disappears with (Y).
4. D The colour of bromine does not disappear with (X) and disappears with (Y).

From the opposite chart: (1st session 2022)
(A) → (HX) (B) → (HX) (C)
Compounds (A) , (B) , (C) are ..........

1. A (A) : an alkene derivative , (B) : an alkyne , (C) : an alkane derivative.
2. B (A) : an alkyne , (B) : an alkene derivative , (C) : an alkane derivative.
3. C (A) : an alkyne , (B) : an alkane derivative , (C) : an alkene derivative.
4. D (A) : an alkene derivative , (B) : an alkene derivative , (C) : an alkane derivative.

The compounds to which Markovnikov's rule can apply are .......... (1st session 2022)

1. A CH₃CHCHCH₃ , CH₃CCCH₃
2. B CH₂CHCH₂CH₃ , CH₃CCCH₃
3. C CH₃(CH₂)₂CH₃ , (CH₃)₂CCH₂
4. D CH₃CCCH₃ , (CH₃)₂CHCH₃

From the opposite reactions: (Trial exam / March 2023)
C₂H₆ + excess HCl → (A)
C₂H₄ + excess HCl → (B)
C₂H₂ + excess HCl → (C)
The order of the molar masses of the organic products (A) , (B) , (C) is ..........

1. A C > B > A
2. B A > C > B
3. C A > B > C
4. D B > C > A

The product of the catalytic hydration of propyne is .......... (1st session 2022)

1. A CH₃CH₂CHO
2. B CH₃COCH₃
3. C CH₃CH₂CH₂OH
4. D CH₃CHOHCH₃

The monomer needed to obtain the polymer used to make floor insulators can be prepared from the reaction of .......... (2nd session 2023)

1. A ethyne with Cl₂
2. B ethyne with HCl
3. C ethene with HCl
4. D ethene with Cl₂

(A) and (B) are unsaturated aliphatic hydrocarbons that do not belong to the same homologous series. When bromine water is added to each of them separately, the products may be .......... (2nd session 2023)

1. A C₂H₅Br , C₂H₂Br₂
2. B C₂H₅Br , C₂H₃Br
3. C C₂H₄Br₂ , C₂H₂Br₂
4. D C₂H₄Br₂ , C₂H₃Br

Three open-chain hydrocarbons (A) , (B) , (C). (1st session 2024)
When 1 mol of each of them burns in excess oxygen:
(A) : gives a number of moles of H₂O(v) < the number of moles of CO₂(g)
(B) : gives a number of moles of H₂O(v) = the number of moles of CO₂(g)
(C) : gives a number of moles of H₂O(v) > the number of moles of CO₂(g)
Which of the following choices is correct?

1. A (C) : cyclopropane , (B) : reacts by substitution.
2. B (B) : ethene , (C) : reacts by addition.
3. C (A) : propyne , (B) : gives a dihydroxy alcohol by oxidation.
4. D (A) : ethyne , (C) : gives acetaldehyde by catalytic hydration.

To obtain hexachloroethane from ethyne, the following processes are needed .......... (1st session 2022)

1. A adding chlorine, then removing hydrogen.
2. B adding hydrogen, then adding chlorine.
3. C adding chlorine, then substituting hydrogen.
4. D adding chlorine, then adding hydrogen.