AIPMT – 2001 – NEETmcqs

The correct acidic order of the following is:


(I)	(II)	(III)

I > II > III
III > I > II
II > III > I
I > III > II

Exam: AIPMT – 2001

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AIPMT - 2001

Alcohols: Preparation & Properties

In preparation of alkene from alcohol using $Al_{2}O_{3}$ which is an effective factor:

Porosity of $Al_{2}O_{3}$
Temperature
Concentration
Surface area of $Al_{2}O_{3}$

Explanation:

HINT: Temperature is very effective factor in dehydration of alcohols.

Explanation:

Temperature is the effective factor for dehydration of alcohol by Al₂O₃. At higher temperautre (350^∘C−380^∘C) 1^∘alcohol undergoes intramolecular dehydration to yield an alkene:

$RCH_{2}CH_{2}OH \: \: \xrightarrow[Al_{2}O_{3}]{350-380^{0}C}\: \: RCH=CH_{2} \, \, +\, \, H_{2} O \, \, \, (Intramolecular \: \:\, \, \, \, dehydration)$

while at lower temperature (220^∘C − 250^∘C) it undergoes intermolecular dehydration to yield to ether.

$RCH_{2}CH_{2}OH \, \, + \, \, \,OH CH_{2}CH_{2}R \xrightarrow \: \: RCH_{2}CH_{2}O CH_{2}CH_{2}R \, \, +\, \, H_{2} O \, \, \, (Intermolecular \, \, \, dehydration)$

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Exam: AIPMT – 2001

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AIPMT - 2001