Directions : (11 - 15) |
Case III : Read the passage given below and answer the following questions from 11 to 15. |
Dehydration of alcohols can lead to the formation of either alkenes or ethers. This dehydration can be carried out either with protonic acids such as cone. \[{{H}_{2}}S{{O}_{4}}\], \[{{H}_{3}}P{{O}_{4}}\] or catalysts such as anhydrous \[ZnC{{l}_{2}}\]or\[A{{l}_{2}}{{O}_{3}}\]. When primary alcohols are heated with cone. \[{{H}_{2}}S{{O}_{4}}\] at 433-443 K, they undergo intramolecular dehydration to form alkenes. Secondary and tertiary alcohols undergo dehydration under milder conditions. |
The ease of dehydration of alcohols follows the order :\[3{}^\circ \text{ }>\text{ }2{}^\circ \text{ }>\text{ }1{}^\circ \]. |
The dehydration of alcohols always occurs in accordance with the Saytzeff's rule. Primary alcohols when heated with protic acid at 413 K, gives dialkyl ether. |
\[C{{H}_{3}}C{{H}_{2}}OH\xrightarrow[433-443\,K]{conc.\,{{H}_{2}}S{{O}_{4}}}C{{H}_{2}}=C{{H}_{2}}+{{H}_{2}}O\] |
\[2C{{H}_{3}}C{{H}_{2}}OH\xrightarrow[413\,K]{conc.\,{{H}_{2}}S{{O}_{4}}}\] |
\[C{{H}_{3}}C{{H}_{2}}-O-C{{H}_{2}}C{{H}_{3}}+{{H}_{2}}O\] |
A) \[{{\left( C{{H}_{3}} \right)}_{2}}CHC{{H}_{2}}OH\]
B) \[{{\left( C{{H}_{3}} \right)}_{3}}COH\]
C) \[C{{H}_{3}}CHOHC{{H}_{3}}\]
D) \[C{{H}_{3}}C{{H}_{2}}C{{H}_{2}}OH\]
Correct Answer: B
Solution :
The order of dehydration of alcohols is \[3{}^\circ >\text{ }2{}^\circ >\text{ }1{}^\circ \].You need to login to perform this action.
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