1, 3, 3-trimethyl-1, 3-propanol

MCQ Questions for Class 12 Medical Chemistry Alcohols, Phenols And Ethers Quiz 5

Which of the following alcohols forms a ketone when oxidized?

0%
1-Propanol
0%
Methanol
0%
2-Methyl-2-propanol
0%
2-Propanol

Explanation

2-propanol (a secondary alcohol) forms a ketone when oxidized.

$\displaystyle CH_3 - \underset { \underset {\displaystyle OH}{|} }{C} H- CH_3 \xrightarrow { \text {oxidation}} CH_3 - \underset { \underset {\displaystyle O}{||} }{C} - CH_3$

1-propanol and methanol (primary alcohols) forms aldehydes when oxidized.

$\displaystyle CH_3 -CH_2- \underset { \underset {\displaystyle OH}{|} }{C} H_2 \xrightarrow { \text {oxidation}} CH_3-CH_2 - \underset { \underset {\displaystyle O}{||} }{C} - H$

$\displaystyle CH_3 -OH \xrightarrow { \text {oxidation}} H- \underset { \underset {\displaystyle O}{||} }{C} - H$

2-methyl-2-propanol (

$\displaystyle (CH_3)_3 C -OH$ ) is a tertiary alcohol whose oxidation requires drastic conditions. The number of

$C$ atoms in the oxidation product are less than the number of

$C$ atoms in the starting material.

The bond angle of the bond

$C-O-C$ in methoxy methane is:

0%
$111.7$
0%
$109$
0%
$108.9$
0%
$180$

Explanation

bond angle =

$111.7^{o}$
Ethers feature C–O–C linkage defined by a bond angle of about 110° and C–O bond length of about 140 pm.

In methoxymethane, the bond angle is

$111.7^{o}$ . Methoxymethane show positive deviation in the bond angle. This is basically due to the steric crowding on carbon atoms of methyl group.

Due to the crowding, the repulsion between bond pair of carbons and lone pair of oxygen is low. Thus, the bond angle of methoxymethane is

$111.7^0$ .

In iodine charge transfer test the color of ether compound formed is:

0%
blue
0%
pale yello
0%
brown
0%
dark red

Explanation

The correct option is

$C$ . Ether forms charge transfer complexes with Iodine to give a brown solution.

$R-O-R'\longrightarrow R'I-+RI+H_2O$

Which of the following is the functional group of an ether?

0%
$R - OH$
0%
$R - O - R$
0%
$R-CO-R'$
0%
$R-COOH$
0%
$RCHO$

Explanation

The correct option is B.

$R-O-R$ is generally the functional group of the ether which is non-polar and does not form hydrogen bonding.

$CH_3OH\xrightarrow{P+I_2}A \xrightarrow{Mg/dry\ ether}B\xrightarrow{HCHO}C\xrightarrow{{H^+/H_2O}}D$

What are

$B$ &

$D$ respectively?

0%
$CH_3MgI$ , $CH_3CHO$
0%
$CH_3MgI$ , $CH_3CH_2OH$
0%
$CH_3MgI$ , $CH_3COOH$
0%
$CH_3MgI$ , $CH_3COCH_3$

Explanation

$CH_3OH\xrightarrow{P+I_2}CH_3I \xrightarrow{Mg/dry\ ether}CH_3MgI\xrightarrow{HCHO}CH_3CH_2OMgI\xrightarrow{{H^+/H_2O}}CH_3CH_2-OH$

Hence

$B$ is the correct answer.

Which of the following can not be formed by hydrolysis of alkenes?

0%
Methanol
0%
Ethanol
0%
Propanol
0%
None of these

On treatment with dilute

$H_2SO_4$ , ethene forms ethanol.

0%
True
0%
False

Explanation

On the reaction of ethane with dilute

${ H }_{ 2 }SO_{ 4 }$ , it terms ethanol.
1157157_522560_ans_2febd731de324143aa3998e60ea3bb53.PNG

Hydrogen chloride and

$SO_2$ are the side products in the reaction of ethanol with thionyl chloride. Which of the following is the main product in this reaction?

0%
$C_2H_5OC_2H_5$
0%
$C_2H_6$
0%
$CH_3Cl$
0%
$C_2H_5Cl$

Explanation

When ethanol is treated with thionyl-chloride, the side product are

$HCl$ and

$S{ O }_{ 2 }$ and main product is

${ C }_{ 2 }{ H }_{ 5 }Cl.$
1174964_522795_ans_68ce62c5060d4822a06facf6482759d5.PNG

Which of the following is used in the manufacture of ethanol?

0%
$C_2H_6$
0%
$C_2H_2$
0%
$CH_4$
0%
$C_2H_4$

Explanation

The correct option is D. Ethanol can be prepared by hydration of ethane in the presence of

$H_{ 2 }O.$
1171649_522790_ans_7637f2936f714b0fb6bd97f8242fdd75.PNG

What type of spectroscopy would be the best tool to analyze a clear and colorless solution for the presence of a functional group like an alcohol group

$(-OH)$ ?

0%
UV spectroscopy.
0%
IR spectroscopy.
0%
Mass spectroscopy.
0%
Photoelectron spectroscopy.

Phenol is a:

0%
crystalline solid
0%
amorphous solid
0%
volatile liquid
0%
nonvolatile liquid

What are X and Y respectively in the following reaction?

$\displaystyle X \xrightarrow[]{PBr_3} C_2H_5Br \xrightarrow[\Delta]{AgOH}Y$

0%
$CH_3OH, C_2H_6$
0%
$C_2H_5OH, C_2H_5AgBr$
0%
$CH_3COOH, CH_3CH_2OH$
0%
$C_2H_5OH, C_2H_5OH$

Explanation

Ethanol when treated with

${ PBr }_{ 3 }$ , it gives biomethane which on further treatment with

$AgOH$ gives back ethanol.
1172857_522792_ans_6044a9ce3157474cade31a8238129923.PNG

An industrial method for the preparation of methanol is:

0%
by catalytic reduction of carbon monoxide
0%
by reacting methane with steam in presence of a catalyst
0%
by reduction of $HCHO$ with $LiAlH_4$
0%
by reduction of $HCHO$ with aqueous $NaOH$

Explanation

An industrial method for the preparation of methanol is by catalytic reduction of carbon monoxide.

$\displaystyle \underset { \displaystyle \text { Synthetic gas } }{\underset { \displaystyle \text { water gas } }{CO+H_2}+H_2} \xrightarrow [ \text { 300 deg C, pressure }]{Cr_2O_3-ZnO} \underset { \displaystyle \text { Methanol } }{CH_3-OH}$

The distillation of rectified spirit gives absolute ethanol.

0%
True
0%
False

Explanation

The distillation of the rectified spirit after the fractional distillation, it gives absolute ethanol which is

$100$ %

Methanol can be prepared when :

0%
iodomethane is heated with moist silver oxide
0%
iodomethane react with sodium in the presence of ether
0%
both A and B
0%
none of these

Explanation

Moist Silver oxide

$Ag_2O + H_2O \rightarrow 2AgOH$

$CH_3-I + AgOH \rightarrow CH_3-OH + AgI$

Therefore, methanol can be prepared when iodomethane is heated with moist silver oxide.

Phenol is soluble in water because :

0%
it is a nonpolar compound
0%
it forms complex with water
0%
it forms hydrogen bond with the water
0%
phenol is not soluble in water

Explanation

The

$-OH$ group in Phenols is involved in the intermolecular hydrogen bonding with water. Thus, phenol is soluble in water.

1014598_584356_ans_09e5823428b4498b84874e9444e39203.PNG

Dehydration of alcohol is an example of which type of reaction?

0%
Substitution
0%
Elimination
0%
Addition
0%
Both $B$ and $C$

The IUPAC name of:

0%
2, 1-dimethyl-1, 3-butanol
0%
4,4-dimethyl-2-pentanol
0%
4-methyl-2, 4-pentanol
0%
1, 3, 3-trimethyl-1, 3-propanol

Explanation

The IUPAC name of the given compound is 4,4-dimethyl-2-pentanol.

The parent hydrocarbon contains 5

$C$ atoms and a

$-OH$ group. Hence, it is pentanol. Two methyl groups are present as substituents on fourth carbon atom and are named as the prefix. The prefix di indicates 2. The numbering is done from the end which gives the lowest locant to the

$C$ atom bearing

$-OH$ group.

Hence, the correct option is

$B$

Which of the following is not true regarding phenol?

0%
Pure phenol is a white crystalline solid
0%
Phenol smell as disinfectant.
0%
It causes immediate white blistering to the skin
0%
None of these

Melting point of phenol is:

0%
$95^0$ C
0%
$43^0$ C
0%
$20^0$ C
0%
$10^0$ C

Explanation

The correct option is

$B$ .

Phenol is crystalline solid and has a definite melting point at

$43$ degree Celsius.

1174683_568550_ans_7ef8ba50823d426eb6d0b9417ec30a31.PNG

Which of the following compound is most acidic?

0%
$Cl-CH_2-CH_2-OH$
0%
0%
0%

Explanation

$NO_2$ shows

$-M$ effect as it placed on ortho group of phenol which stabilizes the phenoxide anion hence it will be most acidic.

Hence, option C is correct.

Melting point of phenol is :

0%
$53^0C$
0%
$43^0C$
0%
$33^0C$
0%
$23^0C$

Explanation

Pure phenols are generally colorless solids or liquids. Phenols (molecular weight

$=94$ ) have the relatively low melting point. So generally exist in liquid form above room temperature.

its melting point is

$43^0C$ .

Molecular weight of phenol is :

0%
$94.11$
0%
$104.11$
0%
$86.11$
0%
$98$

Explanation

Molecular formula of Phenol is

$C_6H_5-OH$

Therefore, moelcular weight:

$6 (Mass \ of \ Carbon) + 6 (Mass \ of \ Hydrogen)+16 (Mass \ of \ Oxygen)$

$=6 \times 12 + 5 \times 1 + 16 \times 1 + 1 \times 1$

$=94.11$

Methanol is called as Marine Methanol beacuse:

0%
it is an essential compound for marine life
0%
it is mostly obtained from deep sea bed
0%
it is used as a marine fuel
0%
it serves as a signal indicator for big ships on burning

Reagents used for industrial preparation of methanol are:

0%
$CO+H_2$
0%
$HCHO+H_2$
0%
$CO_2+H_2$
0%
$HCOOH+H_2$

Explanation

Carbon monoxide and hydrogen react over a catalyst to produce methanol. Today, the most widely used catalyst is a mixture of copper and zinc oxides,supported on alumina.At

$5–10$ MPa (

$50–100$ atm) and 250 °C (482 °F), the reaction is characterized by high selectivity (

$>99.8$ %).

$CO + 2H_2 \longrightarrow CH_3OH$

Common name for methanol is:

0%
volemitol
0%
rubbing alcohol
0%
wood spirit
0%
xylitol

Destructive distillation of wood in the laboratory will result in the formation of :

0%
Ethanol
0%
Methane
0%
Methanol
0%
Butane

The other name for Syngas is:

0%
Producer gas
0%
Water gas
0%
Tear gas
0%
Fuel gas

The major product of Raschig process was taken for litmus test.It was observed that it turned:

0%
red litmus blue
0%
blue litmus red
0%
no change in colour
0%
very slight change in colour from red towards blue

Ether is formed when alkyl halide is treated with sodium alkoxide. This method is known as:

0%
Hoffmann reaction
0%
Williamson synthesis
0%
Wurtz synthesis
0%
Kolbe's reaction

Explanation

Ether is formed when alkyl halide is treated with sodium alkoxide. This method is known as Williamson synthesis.
For example, methyl iodide reacts with sodium methoxide to form dimethyl ether.

$\displaystyle CH_3-I + CH_3-O-Na \rightarrow CH_3-O-CH_3 + NaI$

What is the

$IUPAC$ name of the following compound?

$CH_{3} - CH_{2} - CH_{2} - OH$

0%
Propan-1-ol
0%
Propan-2-ol
0%
Propane-1-ol
0%
Ethane-2-ol

Explanation

In this compound, the number of carbon atoms is 3. So, the parent alkane is propane.

The functional group present is

$-OH$ i.e alcohol.

$-OH$ is present at the first carbon atom

Thus the IUPAC name is Propan - 1 - ol.

Which of the following alcohol has highest solubility in water ?

0%
Tertiary butyl alcohol
0%
Secondary butyl alcohol
0%
Ethylene glycol
0%
Glycerol

When alkyl halide is heated with dry

${ Ag }_{ 2 }O$ , it produces:

0%
ester
0%
ether
0%
ketone
0%
alcohol

Explanation

Alkyl halide on reaction with dry silver oxide gives ether.

$\underset { Alkyl \ halide }{ 2RX } +{ Ag }_{ 2 }O\longrightarrow \underset { ether }{ R-O-R } +2AgX$

What is the formula of tertiary butyl acohol?

0%
$CH_{3} - CH(CH_{3}) - CH_{2} - OH$
0%
$CH_{3} - (CH_{2})_{2}OH$
0%
$CH_{3} - CH(OH) - CH_{2} - CH_{3}$
0%
$(CH_{3})_{3} C - OH$

Explanation

Is the formula of tertiary butyl alcohol as in it

$-OH$ group is attached to tertiary carbon.

In which of the following reactions of alcohol there is no cleavage of C-O bond ?

0%
Dehydration reaction of alcohol
0%
Oxidation reaction of alcohol
0%
Reduction reaction of alcohol
0%
Reaction of alcohol with phosphorus tribromide

Explanation

(a) Dehydration of alcohol
It involves cleavage of C-O bond.

(b) Oxidation of alcohol

$3^o$ alcohols generally do not undergo oxidation however in the presence of

$KMnO_4$ , cleavage of C-C bond takes place to give two acids in which C-O bond remains uncleaved.

$CH_3CH_2OH \overset{LiAlH_4}{\rightarrow} CH_3CH_3$
It involves cleavage of C-OH bond.

(d) Reaction with phosphorus tribromide

$CH_3CH_2OH \overset{PBr_3}{\rightarrow} CH_3CH_2Br$
It also involves cleavage of C-OH bond.

Thus, oxidation reactions of alcohol do not involve cleavage of C-O bond among the given reactions.

Which of the following statement is not correct ?

0%
Phenol is neutralised by sodium carbonate
0%
Phenol is used to prepare analgesic drugs
0%
Solubility of phenol in water is more than that of chlorobenzene
0%
Boiling point of o-nitrophenol is lower than that of p-nitrophenol

Explanation

Phenol does not react with

$Na_2\, CO_3$ because it is weaker acid than carboxylic acid and thereby do not have the strength to substitute or give away its H+ ions to that of weak bases like sodium carbonate.

Phenol is used for the preparation of aspirin which is used as an analgesic as well as antipyretic drugs.

Phenol is more soluble in water than chlorobenzene due to formation of H-bond with water molecules.

o-nitrophenol form intramolecular

$H-$ bonding while p-nitrophenol form intermolecular

$H-$ bonding. Due to this, nature o-nitrophenol has a lower boiling point than p-nitrophenol.

Which of the following represents monohydric alcohol?

0%
$C_nH_{2n}OH$
0%
$C_nH_{2n+1}OH$
0%
$C_nH_{n}O$
0%
$C_nH_{n}OH$

Which of the following compounds decolourizes aqueous bromine and gives white fumes of

$HCl$ on reaction with

$PCl_{5}$ ?

0%
$CH_{3}COCH_{2}CH - CH_{2}$
0%
$CH_{3}CH_{2}CH_{2}CH_{2}CH_{3}$
0%
$CH_{3}CH = CHCH_{2}CH_{2}OH$
0%
$CH_{3}OCH_{2}CH_{2}CH_{2}CH_{2}OH$

Explanation

$CH_3-CH=CH-CH_2-CH_2-OH+PCl_5\longrightarrow K_3C-CH=CH-CH_2-CH_2-Cl+MCl+POCl_3$

$\downarrow$

$Br_2|H_2O$

Colour decolorises due to the presence of double bond.

Diols (I - IV) which react with

$CrO_{3}$ in aqueous

$H_{2}SO_{4}$ and yield products that readily undergo decarboxylation on heating are:

0%
I and II
0%
II and III
0%
II and IV
0%
I and IV

Which of the following is most soluble in water ?

0%
n- butyl alcohol
0%
Iso-butyl alcohol
0%
Tertiary butyl alcohol
0%
None of the above

Dehydration of alcohol is an example of which type of reaction ?

0%
Substitution reaction
0%
Elimination reaction
0%
Rearrangement reaction
0%
Addition reaction

Explanation

Dehydration of alcohol is an example

$\beta$ -elimination. It involves the lose of two atoms/groups from adjacent carbon atoms.

$\underset{ethanol}{\overset{\beta }{CH_3}\overset{\alpha }{CH_2}OH} \overset{alc.KOH}{\rightarrow}\underset{ethene }{CH_2 = CH_2}$

Consider the given reaction:

$\displaystyle CH_3-CH=CH-CH_2-OH \overset{HBr}{\underset{S_N 1}{ \longrightarrow}} [P]$

In the given reaction the product

$[P]$ is:

0%
$CH_3-CH=CH-CH_2-Br$
0%
$CH_3 - \!\!\overset{\,\,\,Br}{\overset{|}{C}}\!\!H - CH = CH_2$
0%
$CH_2=CH-CH=CH_2$
0%
$CH_3 - \overset{\,\,\,Br}{\overset{|}{C}}\!\!H - CH_2 - CH_2 - OH$

Explanation

As the dehydration takes place through

$SN^1$ mechanism so the carbocation intermediate forms.

More stable carbocation gives major product.

The correct answer is

$B$ .

1155653_696609_ans_40b56bfff28d445484d900a178eb3743.png

The order of reactivity of the following alcohols towards conc.

$HCl$ is:

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

What is the hybridisation of carbon and oxygen in electronic structure of ether?

0%
$sp^{3}$ and $sp^{2}$
0%
$sp^{3}$ and $sp^{3}$
0%
$sp$ and $sp$
0%
$sp^{2}$ and $sp^{2}$

Explanation

$sp^{3}$ (4-bond pairs) and

$sp^{3}$ (2-bond pairs and 2-lone pairs) hybridisations of carbon and oxygen in the electronic structure of an ether.

Which is the only alcohol that can be prepared by the indirect hydration of alkene?

0%
Ethyl alcohol
0%
Propyl alcohol
0%
Isobutyl alcohol
0%
Methyl alcohol

Explanation

Alkene is treated with sulfuric acid to give alkyl sulphate esters. In the case of ethanol production, this step can be written:

$H_2SO_4 + C_2H_4 \rightarrow C_2H_5-O-SO_3H$

Subsequently, this sulphate ester is hydrolyzed to regenerate sulphuric acid and release ethanol:

$C_2H_5-O-SO_3H + H_2O \rightarrow H_2SO_4 + C_2H_5OH$

This two step route is called the "indirect process".

Only in case of ethane it will produce ethyl alcohol while in case of other alkenes product is according to

$Markovnikov's\ Rule$ .

Methyl alcohol can't be produced by indirect hydration of alkene.

The IUPAC name for the compound given below is:

0%
$(2R, 3Z)$ - 7 - phenylhept - 3- en - 2 - ol
0%
$(2S, 3Z)$ - 7 - phenylhept - 3- en - 2 - ol
0%
$(2R, 3E)$ - 7 - phenylhept - 3- en - 2 - ol
0%
$(2S, 3E)$ - 7 - phenylhept - 3- en - 2 - ol

Among the following compounds, the one which can be dehydrated most easily is:

0%
$CH_{ 3 }-CH_{ 2 }-\overset { \overset { CH_{ 3 } }{ | } }{ \underset { \underset { OH }{ | } }{ C } }-CH_{ 2 }CH_{ 3 }$
0%
$CH_3-CH_2-CH_2-\underset { \underset { OH }{ | } }{ C } H-CH_3$
0%
$CH_3-CH_2-CH_2-CH_2-CH_2-OH$
0%
$(CH_3)_2CH-CH_2-CH(OH)-CH_3$

Explanation

The compound which can be easily dehydrated will form most stable carbocation after removal of

$H_{ 2 }O$ molecule.

Since stability of carbocation follows 3 degree> 2 degree> 1 degree,

so, compound

$A$ is most easily dehydrated.

Option A is correct.

1036615_771013_ans_ed4cd4dc24ec4078b3376c059ee2b08e.png

Which of the following statements is incorrect regarding preparation of alcohols?

0%
Aldehydes and Ketones on catalytic reduction by [H] give primary alcohol and secondary alcohol respectively
0%
Ketones on reaction with Grignard’s reagent gives tertiary alcohol
0%
Aldehydes on reaction with Grignard’s reagent gives primary or secondary alcohol
0%
Alkyl halides on reaction alcoholic potash gives alcohol

Which of the following phenols has lowest solubility in water?

0%
Phenol
0%
o-Nitrophenol
0%
m-Nitrophenol
0%
p-Nitrophenol

Explanation

$O-$ nitrophenol undergoes creation because of intra-moleculer hydrogen bonding. So, it is least soluble.
1174666_776124_ans_702a802666e44d3c81599b2a6935a1ea.PNG

1174666_776124_ans_702a802666e44d3c81599b2a6935a1ea.PNG

An Alcohol X pass over Cu at 300C, then produced compound decolourised Bromine liquid, X is:

Explanation

Since the compound formed finally decolourises Bromine water, so it must be alkene. Now

$3$ degree alcohol were dehydrated with heated Cu forms alkene. So,

$X$ is a

$3$ degree alcohol.
1037654_856007_ans_91c86a5b2a0243d58256facf1362549b.PNG

CBSE Questions for Class 12 Medical Chemistry Alcohols, Phenols And Ethers Quiz 5 - MCQExams.com

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Practice Class 12 Medical Chemistry Quiz Questions and Answers

CBSE Questions for Class 12 Medical Chemistry Alcohols, Phenols And Ethers Quiz 5 - MCQExams.com

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Practice Class 12 Medical Chemistry Quiz Questions and Answers

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