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Assertion : trans-butene on reaction with bromine forms racemic mixture.
Reason : trans-compound in trans addition forms two types of stereoisomers.
Options:
Reason : trans-compound in trans addition forms two types of stereoisomers.
Solution:
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Verified Answer
The correct answer is:
If both assertion and reason are false.
With trans-but-2-ene, the product of \(\mathrm{Br}_2\) addition is optically inactive due to the formation of symmetric meso compounds.
In general, for symmetrical alkenes and symmetrical reagents, the addition takes place as:
\(\begin{gathered}
\text { cis-alkene }+ \text { syn-addition } \rightarrow \text { meso } \\
\text { trans-alkene }+ \text { syn-addition } \rightarrow \text { racemic } \\
\text { cis-alkene }+ \text { anti-addition } \rightarrow \text { racemic } \\
\text { trans-alkene }+ \text { anti-addition } \rightarrow \text { meso }
\end{gathered}\)
In general, for symmetrical alkenes and symmetrical reagents, the addition takes place as:
\(\begin{gathered}
\text { cis-alkene }+ \text { syn-addition } \rightarrow \text { meso } \\
\text { trans-alkene }+ \text { syn-addition } \rightarrow \text { racemic } \\
\text { cis-alkene }+ \text { anti-addition } \rightarrow \text { racemic } \\
\text { trans-alkene }+ \text { anti-addition } \rightarrow \text { meso }
\end{gathered}\)
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