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Stabilities of alkanes can be compared b...

Stabilities of alkanes can be compared by converting these compounds to a common product and comparing the amount of the heat given off. One possiblitiy would be to measure the heat of combustion from converting alkenes to `xo_(2)` and `H_(2)O` . The heats of combustion are of large values and measuring small difference in these large numbers is difficult. Alkene of the lowest heat of combustion among isomeric alkenes is of the lowest energy and is most stable.
Th stability of alkenes is often compared by meansuring the ehat of hydrogenation `9` heat given off, `Delta H_(h)^(@)` during catalytic hydrogenation. The heat of hydrogenation is in smal number, which provides more accurate energy difference.
For a compound containing more than one double bond, `Delta_(h)^(@)` is the sum of heat of hydrogenation of individual double bonds. For non `-` conjugated diens, this additive relatioship is found to hold. For conjugated dienes, however, the measured value is slightly lower than expected. Cumulated dienes, which are even less stable than non `-` conjugated dienes.
The more stable is the alkene, lower is the heat of combustion and heat of hydrogenation. More highly substituted double bonds are usually more stable. In case of cyclokanes, compounds having higher angle strin are less stable.
Arrange the following compounds according to their increasing heat of combustion. `I.` `1-`Butene
`II.` cis `-2-`Butene
`III.` trans `-2-`Butene
`IV.` `2-` Methyl propene

A

`(IV)gt(I)lt(II)lt(III)`

B

`(I)lt(II)lt(IV)lt(III)`

C

`(IV)gt(III)lt(II)lt(I)`

D

`(I)lt(II)lt(III)lt(IV)`

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To solve the problem of arranging the given alkenes according to their increasing heat of combustion, we will follow these steps: ### Step 1: Understand Stability and Heat of Combustion The stability of alkenes is inversely related to their heat of combustion. More stable alkenes will have lower heats of combustion. Therefore, we need to determine the stability of each alkene listed. ### Step 2: Analyze Each Alkene 1. **1-Butene**: This is a mono-substituted alkene (one alkyl group attached to the double bond), making it the least stable. 2. **Cis-2-Butene**: This is a disubstituted alkene (two alkyl groups on the double bond) with both groups on the same side, making it more stable than 1-butene. 3. **Trans-2-Butene**: This is also a disubstituted alkene but with the groups on opposite sides, making it more stable than cis-2-butene. 4. **2-Methylpropene**: This is a highly substituted alkene (three alkyl groups attached to the double bond), making it the most stable of the four. ### Step 3: Rank the Alkenes by Stability Based on the analysis: - **Most Stable**: 2-Methylpropene (4) - **Next Stable**: Trans-2-Butene (3) - **Next**: Cis-2-Butene (2) - **Least Stable**: 1-Butene (1) ### Step 4: Determine the Order of Increasing Heat of Combustion Since more stable alkenes have lower heats of combustion, we can reverse the order of stability to find the order of increasing heat of combustion: 1. **1-Butene** (highest heat of combustion) 2. **Cis-2-Butene** 3. **Trans-2-Butene** 4. **2-Methylpropene** (lowest heat of combustion) ### Final Order Thus, the order of the compounds according to their increasing heat of combustion is: - **2-Methylpropene (IV) < Trans-2-Butene (III) < Cis-2-Butene (II) < 1-Butene (I)** ### Answer: **IV < III < II < I** ---
To solve the problem of arranging the given alkenes according to their increasing heat of combustion, we will follow these steps: ### Step 1: Understand Stability and Heat of Combustion The stability of alkenes is inversely related to their heat of combustion. More stable alkenes will have lower heats of combustion. Therefore, we need to determine the stability of each alkene listed. ### Step 2: Analyze Each Alkene 1. **1-Butene**: This is a mono-substituted alkene (one alkyl group attached to the double bond), making it the least stable. 2. **Cis-2-Butene**: This is a disubstituted alkene (two alkyl groups on the double bond) with both groups on the same side, making it more stable than 1-butene. ...
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Stabilities of alkanes can be compared by converting these compounds to a common product and comparing the amount of the heat given off. One possiblitiy would be to measure the heat of combustion from converting alkenes to xo_(2) and H_(2)O . The heats of combustion are of large values and measuring small difference in these large numbers is difficult. Alkene of the lowest heat of combustion among isomeric alkenes is of the lowest energy and is most stable. Th stability of alkenes is often compared by meansuring the ehat of hydrogenation 9 heat given off, Delta H_(h)^(@) during catalytic hydrogenation. The heat of hydrogenation is in smal number, which provides more accurate energy difference. For a compound containing more than one double bond, Delta_(h)^(@) is the sum of heat of hydrogenation of individual double bonds. For non - conjugated diens, this additive relatioship is found to hold. For conjugated dienes, however, the measured value is slightly lower than expected. Cumulated dienes, which are even less stable than non - conjugated dienes. The more stable is the alkene, lower is the heat of combustion and heat of hydrogenation. More highly substituted double bonds are usually more stable. In case of cyclokanes, compounds having higher angle strin are less stable. The wrong option among the following statements is :

Stabilities of alkanes can be compared by converting these compounds to a common product and comparing the amount of the heat given off. One possibility would be to measure the heat of combustion from converting alkenes to CO_(2) and H_(2)O . The heats of combustion are of large values and measuring small difference in these large numbers is difficult. Alkene of the lowest heat of combustion among isomeric alkenes is of the lowest energy and is most stable. Th stability of alkenes is often compared by meansuring the ehat of hydrogenation 9 heat given off, Delta H_(h)^(@) during catalytic hydrogenation. The heat of hydrogenation is in smal number, which provides more accurate energy difference. For a compound containing more than one double bond, Delta_(h)^(@) is the sum of heat of hydrogenation of individual double bonds. For non - conjugated diens, this additive relatioship is found to hold. For conjugated dienes, however, the measured value is slightly lower than expected. Cumulated dienes, which are even less stable than non - conjugated dienes. The more stable is the alkene, lower is the heat of combustion and heat of hydrogenation. More highly substituted double bonds are usually more stable. In case of cyclokanes, compounds having higher angle strin are less stable. Which statement is false ?

Stabilities of alkanes can be compared by converting these compounds to a common product and comparing the amount of the heat given off. One possibility would be to measure the heat of combustion from converting alkenes to CO_(2) and H_(2)O . The heats of combustion are of large values and measuring small difference in these large numbers is difficult. Alkene of the lowest heat of combustion among isomeric alkenes is of the lowest energy and is most stable. Th stability of alkenes is often compared by meansuring the ehat of hydrogenation 9 heat given off, Delta H_(h)^(@) during catalytic hydrogenation. The heat of hydrogenation is in smal number, which provides more accurate energy difference. For a compound containing more than one double bond, Delta_(h)^(@) is the sum of heat of hydrogenation of individual double bonds. For non - conjugated diens, this additive relatioship is found to hold. For conjugated dienes, however, the measured value is slightly lower than expected. Cumulated dienes, which are even less stable than non - conjugated dienes. The more stable is the alkene, lower is the heat of combustion and heat of hydrogenation. More highly substituted double bonds are usually more stable. In case of cyclokanes, compounds having higher angle strin are less stable. In which of the following is Delta H^_(h)^(@) the maximum ?

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