Question and answer about alkynes

1.what is the acetylene?

a. the material that used in hydrocarbon reaction

b the material that resulted by the alkynes reaction

c. the material that needed to do the reaction

d. the starting material for the preparation of many useful compound

e. the yield of the reactions

2. what is one of the product of methane process that heated to a very high temperature?

a. acetylene

b. propanes

c. hydrogen

d. ethane

e. water

3. what is the name of this structure:

CH3 C2H5

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CH2–C≡C–CH–CH–CH3

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CH3

a. 5,6–dimetil 3– heptuna

b. 2,3–dimetil 4– heptuna

c. 5,6–dimetil 3– oktuna

d. 3,4–dimetil 4– oktuna

e. 6–etil 5–dimetil 3– heptuna

4. what is the function of addition of halides to the alkynes?

a. to fast the alkynes reaction

b. to make stronger the alkynes reaction

c. there is no impact if the alkynes we add by halides

d. to increase the velocity of the alkynes reaction

e. to opened the triple bond become double bond and then single bond

5. what is the final result of butyne if we adding by hydrogen chloride?

a. 2– chloro butene

b. 2,2– dichloro butene

c. 2– chloro butane

. d. 2,2– dichloro butyne

e. 2,2– dichloro butane

6. what is the different between alkynes and alkanes based on their physical properties?

a. boiling point of more then alkanes

b. alkynes are more soluble in solvent of low polarity than alkanes

c. alkynes is ore slightly soluble in water than alkanes

d. the reation of alkynes is faster than alkanes

e. the density of alkynes is less than the alkanes

7. The compound named 2-butyne has

a. a chain of four carbon atoms with a triple bond between C2 and C3
b. a chain of four carbon atoms with a double bond between C1 and C2
c. a chain of four carbon atoms with a triple bond between C1 and C2
d. a chain of four carbon atoms with a double bond between C2 and C3

e. a chain of four carbon atoms with a single bond between C2 and C3

8. The addition of HCl to 4-methyl-2-pentyne follows Markovnikov's Rule. The product is

a. 2,2– dichloro – 4 methyl pentane

b. 2– dichloro – 4 methyl pentane

c. 2,2– dichloro butyne

d. 2,2– dichloro butane

e. . 2,2– dichloro butane

answer:

1. answer :D.

Reason: because acetylene is used as a starting material for preparation of many useful compound.

2. answer : A

Reason: because acetylene is one of product of ethane process that heated to a very high temperature.

3. answer : C

Reason : because the longest chain is 8 so it is oktuna and the branch is placed in number 5,6 atom C. and the triple bond is placed in the third of atom C

4. answer : E

Because if we add the alkynes with halide the triple bond become opened.

Ex: Br Br Br

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– C ≡ C – + Br2 → C = C + Br2 → – C – C –

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Br Br Br

5. answer: E

Reason : because based on the reaction :

CH3 – CH2 – C ≡ CH + HCl → CH3 – CH2 – C = CH2

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Cl

Cl

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CH3 – CH2 – C = CH2 + HCl → CH3 – CH2 – C = CH2

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Cl Cl

6. answer: C

Reason : because alkynes are only very slightly soluble in water although they are somewhat more soluble than alkanes.

7. answer : A

Reason : because based on the structure:

C – C ≡ C – C

8. answer : A

Reason : based on the reaction:

Cl

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CH3 – C ≡ C – CH – CH3 + HCl → CH3 – C =C – CH – CH3

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CH3 CH3

Cl Cl

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CH3 – C =C – CH – CH3 + HCl → CH3 – C – CH – CH – CH3

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CH3 Cl

2,2– dichloro – 4 methyl pentane