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A hydrocarbon, ‘X’(C(3)H(4)) decolourise...

A hydrocarbon, `‘X’(C_(3)H_(4))` decolourise bromine in carbon tetrachloride forming ‘Y’ . ‘X’ gave a red precipitate of a compound ‘Z’ with ammonical cuprous chloride and formed a carbonyl compound with dilute sulphuric acid in the presence of `Hg^(+2)` ions. X, Y, and Z are given by the set -

A

`CH_(2)=C=CH_(2), CH_(2)Br–CBr_(2)–CH_(2)Br, CH_(3)–C-=C–Cu`

B

`CH_(3)–C-=CH, CH_(3)–CBr_(2)–CHBr_(2), CH3–C-=C–Cu`

C

`CH_(3)–C-=CH, CH_(3)–CBr=CHBr, CH_(2)Cu–C-=CH`

D

`CH_(2)=C=CH_(2), CH_(2)Br–CH=CHBr, CH_(3)–C-=C–Cu`

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AI Generated Solution

The correct Answer is:
To solve the problem step by step, we will analyze the given information about hydrocarbon `X (C3H4)` and its reactions. ### Step 1: Identify the structure of hydrocarbon `X` Given that `X` has the molecular formula `C3H4`, we can calculate its degree of unsaturation (double bond equivalent) using the formula: \[ \text{Degree of Unsaturation} = \frac{(2C + 2 - H)}{2} \] Substituting the values: \[ \text{Degree of Unsaturation} = \frac{(2 \times 3 + 2 - 4)}{2} = \frac{(6 + 2 - 4)}{2} = \frac{4}{2} = 2 \] This indicates that `X` contains two double bonds or one triple bond. ### Step 2: Determine the type of hydrocarbon Since `X` decolorizes bromine in carbon tetrachloride, it indicates that `X` is an alkyne (specifically a terminal alkyne). The structure can be represented as: \[ \text{X} = \text{CH}_3\text{C} \equiv \text{C} \text{H} \] ### Step 3: Identify compound `Y` When `X` reacts with bromine in carbon tetrachloride, it undergoes an addition reaction, resulting in a dibromo compound. The reaction can be represented as: \[ \text{CH}_3\text{C} \equiv \text{C} \text{H} + \text{Br}_2 \rightarrow \text{CH}_3\text{CBr}_2\text{CBr}_2\text{H} \] This compound `Y` is a colorless tetrabromoalkene. ### Step 4: Identify compound `Z` The hydrocarbon `X` reacts with ammoniacal cuprous chloride, which is a test for terminal alkynes. The reaction produces a red precipitate, which is a copper(I) acetylide. The reaction can be represented as: \[ \text{CH}_3\text{C} \equiv \text{C} \text{H} + \text{CuCl} + \text{NH}_3 \rightarrow \text{CH}_3\text{C} \equiv \text{C-Cu} + \text{NH}_4\text{Cl} \] Thus, compound `Z` is `CH3C≡C-Cu`. ### Step 5: Identify the carbonyl compound formed When `X` is treated with dilute sulfuric acid in the presence of `Hg^(2+)` ions, it forms a carbonyl compound through hydration of the alkyne. The reaction can be represented as: \[ \text{CH}_3\text{C} \equiv \text{C} \text{H} + \text{H}_2\text{SO}_4 + \text{Hg}^{2+} \rightarrow \text{CH}_3\text{C}(=O)\text{H} \] This results in the formation of acetone (or propan-2-one). ### Final Summary of Compounds - **X**: `CH3C≡CH` (1-butyne) - **Y**: `CH3CBr2CBr2H` (tetrabromoalkene) - **Z**: `CH3C≡C-Cu` (copper(I) acetylide)
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MOTION-HYDROCARBON -Exercise - 1
  1. Which can yield acetylene in single step

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  2. For preparing methyl acetylene, we take -

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  3. In the reaction CH(3)CH(2)C Cl(2)CH(3)overset(x)rarrCH(3)C-=C CH(3) ...

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  4. CH-=C-COOHoverset(HgSO(4) // H(2)SOH(4))rarr product (A) is

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  5. Ethyne adds on HCl to first give a-

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  6. The catalyst required for the reaction HC-=CH+dil.H(2)SO(4)overset("...

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  7. Hydration of propyne gives -

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  8. By the addition of CO and H(2)O on ethyne, the following is obtained -

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  9. Westrosol is a solvent & it is prepared by -

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  10. The reaction HC-=CHrarr CHCl(2)CHO takes place in

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  11. By the action of hydrobromic acid on ethyne we get -

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  12. Reaction of alkenes and alkynes with hypochlorous acid is called -

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  13. The alkyne which gives pyruvic acid (CH(3)COCOOH) on oxidation with al...

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  14. An alkyne which gives two moles of acetic acid on ozonolysis is -

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  15. An alkyne C(7)H(12) when reacted with alkaline KMnO(4) followed by aci...

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  16. Which one of these will react with sodium metal-

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  17. A compound (C(5)H(8)) reacts with ammoniacal AgNO(3) to give a white p...

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  18. Which one of the following compounds will give white preciptate with t...

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  19. A mixture of CH(4),C(2)H(4) and C(2)H(2) gases are passed through a Wo...

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  20. A hydrocarbon, ‘X’(C(3)H(4)) decolourise bromine in carbon tetrachlori...

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