MCQ Questions for Class 12 Engineering Chemistry Alcohols,Phenols And Ethers Quiz 12

In order to obtain diethyl ether from ethanol, the latter is taken in:

0%
In equal amount of sulphuric acid
0%
In slightly lesser amount of sulphuric acid
0%
In excess amount of sulphuric acid
0%
In far lesser amount of sulphuric acid

Substrate that readily do not show

$E_1$ reaction is:

Identify 'Z' in the following reaction series,

$CH_3CH_2CH_2Br \xrightarrow {aq. NaOH} [X] \xrightarrow[Heat]{Al_2O_3} [Y] \xrightarrow{HOCl} [Z]$

Find :

Arrange the following compounds in order of decreasing acidity:

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I > II > III > IV
0%
III > I > II > IV
0%
IV > III > I > II
0%
II > IV > I > III

How many carbon atom are present in third homologue of methyl ether?

0%
$1$
0%
$2$
0%
$3$
0%
$4$

Explanation

Methyl ether is

$CH_{3}OCH_{3}$

Next homologue is obtained by adding

$-CH_{2}$ group i.e.

$CH_{3}OCH_{2}CH_{3}$ .

$\therefore C$ atoms

$=3$

Again, adding 1 more

$-CH_{2}$ group,

$CH_{3}OCH_{2}CH_{2}CH_{3}$

$\therefore$ Number of carbon atoms in 3rd homologue

$=4$

Explanation

When alcohols are heated with conc.

$H_2SO_4$ , they undergo dehydration to form alkenes.

formation of alkenes depends upon two factors :-

1) Dehydration of alcohols occurs through internmeatiate carbocation formation and carbocation stability follows the order

$3^o > 2^o > 1^o$ . So,

$3^o$ carbonation intermediate will be most stable than

$2^o$ and

$1^o$ .

2) Saytzeff rule : - More highly subsituted alkene is the major product.

1107468_1178246_ans_49ee04ee0a104ae5b659f38ccdae6c2e.png

What is order of decreasing reactivities of following alcohols towards nucleophilic substitution with HBr ?

Explanation

Higher the stability of carbocation, higher the reactivity towards Nucleophillic substitution with

$HBr$ .

If electron- donating group, is present higher the stability of carbocation.

Here, the above image is highly stable.

1100281_1225068_ans_77e2a40452e847efbef0b676c23e8686.PNG

Molecule which does not oxidise using PCC?

The major product is:

Dehydration by conc.

$H_2SO_4$ is the most difficult in:

Which one of the following will most readily dehydrated in acidic medium?

0%
$1^0-alcohol$
0%
$2^0-alcohol$
0%
$3^0-alcohol$
0%
All are equal

In the following reaction X is :-

$_{20}Ca^{40}+X \rightarrow _{21}Sc^{43} + _1H^1$

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Electron
0%
Positrom
0%
alpha particle
0%
proton

What is the total number of carbon atoms in

$P_1$ to

$P_7$ products ?.

0%
$91$
0%
$92$
0%
$93$
0%
$94$

Product C is:

0%
0%
0%
0%
Mixture of 1 and 2

Identify major products

$r_1,r_2$ and

$r_3$ in the given reaction.

In the reaction sequence,

$2CH_{3}CHO \xrightarrow []{OH^{-}}A\xrightarrow []{\Delta}B\ ;$

the product

$B$ is:

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$CH_{3}-CH_{2}-CH_{2}-CH_{2}-OH$
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$CH_{3}-CH=CH-CHO$
0%
$CH_{3}-CH_{2}-CH_{2}-CH_{3}$
0%
$CH_3-\overset {\displaystyle {\overset {\displaystyle O} {||}}}{C}-CH_3$

The following change takes place in the reactant?

0%
Rearrangement of $C_{1} - C_{2}$ bond
0%
Shift of methyl group from $C_{3}$
0%
Hydride shift from $C_{2}$
0%
Loss of $H^{+}$ from alcoholic group

The IUPAC name of the following compound is:

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$2$ -ethylbutan- $2$ -ol
0%
$1$ -ethy- $1$ -methylpropan- $1$ -ol
0%
$3$ -methyl pentan- $3$ -ol
0%
diethylethanol

$(CH_{3})_{2}CHCH_{3}$

$\underrightarrow { HN{ O }_{ 2 } }$ ?

0%
$n-$ butyl alcohol
0%
isobutyl alcohol
0%
tetiary butyl alcohol
0%
secondary butyl alcohol

Which of the following alcohols will dehydrate most rapidly when treated with conc.

$H_2SO_4$ ?

Compare the acidic strength of the above compounds.

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$i > ii > iii$
0%
$ii > iii > i$
0%
$iii > ii > i$
0%
$iii > i > ii$

Which of the following is unsymmetrical ether?

0%
$C_6H_5-O-C_6H_5$
0%
$CH_3-O-C_2H_5$
0%
$C_2H_5-C_2H_5$
0%
$CH_3-O-CH_3$

For which of the following ethers, Williamson's synthesis is a favourable method of preparation :

0%
${ H }_{ 3 }C-\overset { \overset { { CH }_{ 3 } }{ | } }{ \underset { \underset { { CH }_{ 3 } }{ | } }{ C } } -O-\overset { \overset { { CH }_{ 3 } }{ | } }{ \underset { \underset { { CH }_{ 3 } }{ | } }{ C } } -CH_{ 3 }$
0%
$CH_2=CH-O-CH=CH_2$
0%
0%
$CH_2=CH-CH_2-O-CH_2-CH=CH_2$

Choose the compound that shows a precipitate readily on treatment with anhydrous $ZnCl_2$ in concentrated hydrochloric acid ?

Which of the following will react most readily with

$HI$ ?

0%
$CH_3OH$
0%
$(CH_3)_3COH$
0%
$CH_3CH_2OH$
0%
$(CH_3)_2CHOH$

Dehydration of following alcohols follows the order:

0%
$I<II<III<IV$
0%
$II<III<I<IV$
0%
$I<II<IV<III$
0%
$III<I<II<IV$

The increasing order of boiling point for the following compounds is:

$(1)$

${C_2}{H_5}OH$

$(2)$

${C_2}{H_5}Cl$

$(3)$

${C_2}{H_5}C{H_3}$

$(4)$

${C_2}{H_5}OC{H_3}$

0%
(III)<(IV)<(II)<(I)
0%
(IV)<(III)<(I)<(II)
0%
(II)<(III)<(IV)<(I)
0%
(III)<(II)<(I)<(IV)

Which of the following alcohols can be prepared by direct hydration of the corresponding alkene in presence of 50% sulphuric acid?

0%
Butan-1-ol
0%
Butan-2-ol
0%
2-Methylpropan -1-ol
0%
2-Methylpropan-2-ol

$1,2$ dihydroxy benzene
ii-

$1,3$ dihydroxy benzene
iii-

$1,4$ dihydroxy benzene
The increasing order of boiling points of the above mentioned alcohols is

0%
$i < ii < iii$
0%
$ii < iii < i$
0%
$iii < ii < i$
0%
$ii < i < iii$

How many pi(

$\pi$ ) electron are there in the following molecule?

0%
$4$
0%
$6$
0%
$8$
0%
$10$

ortho-Nitrophenol is less soluble in water than p- and m-Nitrophenol because:

0%
Melting point of o-nitrophenol is lower than of m- and p- isomers
0%
o-Nitrophenol is more volatile in steam than those of m- and p- isomers
0%
o- Nitrophenol shows intramolecular H- bonding
0%
o- Nitrophenol shows intermolecular H- bonding

Which of the following will undergo dehydration fast?

Among the following compounds which can be dehydrated very easily is-

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$CH_{3}-CH_{2}-CH_{2}-CH_{2}-CH_{2}OH$
0%
$CH_3-CH_2-CH_2-\overset{OH}{\overset{|}{CH}}-CH_3$
0%
$CH_3-CH_2-\overset{CH_3}{\overset{|}{\underset{OH}{\underset{|}{C}}}}-CH_2-CH_3$
0%
$CH_3-CH_2-\underset{CH_3}{\underset{|}{CH}}-CH_2-CH_2-OH$