Alcohols Phenols and Ethers Test

Result

Alcohols Phenols and Ethers Test - 64

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Weekly Quiz Competition

Question 1
1 / -0

Select the incorrect synthesis.

A

B

C

D

Solution

The synthesis of option D is incorrect as it is nucleophilic aromatic substitution reaction which requires drastic conditions. Under these conditions, the sodium alkoxide undergoes elimination reaction to form an alkene.
Question 2
1 / -0

In which of the following solvents, KI has highest solubility? The dielectric constant $$(\epsilon)$$ of each liquid is given in parentheses.

A
$$ C_{6}H_{6}(\epsilon =0)$$

B
$$(CH_{3})_{2}CO(\epsilon =21)$$

C
$$CH_{3}OH(\epsilon =32)$$

D
$$CCl_{4}(\epsilon =0)$$

Solution

KI is an ionic compound. Hence, it will be most soluble in apolar solvent, which has a high value of dielectric constant. Hence, $$CH_3OH$$ with the highest value of dielectric constant among the given options will provide high solubility.
Question 3
1 / -0

For the reaction the major product is:

A

B

C

D

Solution

A ring expansion creates the six membered carbocation intermediate.
Question 4
1 / -0

The boiling point of phenols are higher than the hydrocarbons of comparable masses due to:

A
more polarising power

B
presence of hydrogen bonding

C
resonance stabilisation

D
acidic character

Solution

The boiling point of compound is effected by forces of attraction existing between molecules. Hydrogen bonding is a stronger force of attraction existing between molecules of phenols as compared to vander waals forces of attraction existing between alkane molecules. (they are weaker forces)
$$\therefore$$ Boiling point of phenol is more than hydrocarbon due to presence of hydrogen bonding.
Question 5
1 / -0

Identify the correct sequence of given steps for the conversion of calcium carbide to methyl alcohol.
(a) Reaction with aqueous $$KOH$$
(b) Hydrolysis
(c) Reaction with soda lime
(d) Reaction with $$Ha{SO}_{4}/{H}_{2}{SO}_{4}$$
(e) Reaction with $$Hg{SO}_{4}$$
(f) Reaction with $$P{Cl}_{5}$$

A
$$b\ d\ e\ c\ f\ a$$

B
$$b\ d\ c\ a\ f\ e$$

C
$$b\ f\ d\ e\ a\ c$$

D
$$d\ b\ c\ e\ f \ a$$

Solution

Steps for the conversion of calcium carbide to methyl alcohol:
(b) Hydrolysis
(d) Reaction with $$Ha{SO}_{4}/{H}_{2}{SO}_{4}$$
(e) Reaction with $$Hg{SO}_{4}$$
(c) Reaction with soda lime
(f) Reaction with $$P{Cl}_{5}$$
(a) Reaction with aqueous $$KOH$$
$$CaC_2 + 2 H_2O\rightarrow C_2H_2 + Ca(OH)_2 \Rightarrow C_2H_2 + H_2SO_4/ HgSO_4 \rightarrow CH_3CHO
\Rightarrow CH_3CHO + H_2SO_4\rightarrow CH_3COOH \Rightarrow CH_3COOH + NaOH + CaO \rightarrow CH_3COONa
\Rightarrow CH_3COONa + PCl_5 \rightarrow CH_3Cl\Rightarrow CH_3Cl + KOH \rightarrow CH_3OH$$
Question 6
1 / -0

Which of the following has lowest boiling point?

A
$$p$$-nitrophenol

B
$$m$$-nitrophenol

C
$$o$$-nitrophenol

D
phenol

Solution

o-nitrophenol forms intramolecular Hydrogen bond and no association occurs whereas molecules of p-nitrophenol get associated through intermolecular Hydrogen bonding and boils relatively at higher temperature (above the boiling point of water). Hence, only ortho-nitrophenol is steam volatile.
Question 7
1 / -0

The correct order of acid strength of the following substituted phenols in water at $${28}^{o}C$$ is:

A
p-nitrophenol< p-fluorophenol< p-chlorophenol

B
p-chlorophenol<p-fluorophenol<p-nitrophenol

C
p-fluorophenol< p-chlorophenol< p-nitrophenol

D
p-fluorophenol< p-nitrophenol< p-chlorophenol

Solution

The order of electron withdrawing tendency from benzene ring is:
$$-F< -Cl< -{NO}_{2}$$

p-chlorophenol is more acidic because fluorine and carbon have identical p orbitals and because of that there overlapping is perfect .Hence it cancels +R effect and -I effect. Thus making p-fluorophenol is less acidic.

$$\therefore$$ Correct order of acidic strength of substituted phenols will be as shown in option C.
Question 8
1 / -0

Ethanol is produced by/from :

A
ethene

B
fermentation of sugars

C
both A and B

D
none of the above

Solution

Formation of Ethanol:

$$\mathrm{\underset{Ethene}{H_2C=CH_2} \xrightarrow[H_2O]{H_2SO_4} \underset{Ethanol}{H_3C-CH_2OH}}$$

$$\mathrm{\underset{Glucose(Sugar)}{C_6H_12O_6} \xrightarrow{Zymase \ enzyme} \underset{Ethanol}{C_2H_5OH}}$$

So, Ethanol can be formed from Ethene and Fermentation of sugar.

Hence, Option "C" is the correct answer.
Question 9
1 / -0

$$R-OH\xrightarrow{PBr_3}A\xrightarrow[]{Mg/Dry \ ether}B\xrightarrow[]{HCHO}C\xrightarrow[]{H^+/H_2O}D$$

What are $$A,B,C$$ & $$D$$ respectively?

A
$$R-Br,R-Br-Mg,R-CH_2Mg-Br,R-CH_2CHO$$

B
$$R-Br,R-Mg-Br,R-CH_2-O-Mg-Br,R-CH_2CHO$$

C
$$R-Br,R-Mg-Br,R-CH_2-O-Mg-Br,R-CH_2OH$$

D
$$R-Br,R-Mg-Br,R-CH_2-Br,R-CH_2OH$$

Solution

$$R-OH\overset{PBr_3}{\rightarrow}R-Br\xrightarrow[]{Mg/Dry

ether}R-Mg-Br\xrightarrow[]{HCHO}R-CH_2-O-Mg-Br\xrightarrow[]{H^+/H_2O}RCH_2OH$$

So the correct order is $$R-Br,R-Mg-Br,R-CH_2-O-Mg-Br,R-CH_2OH$$

Hence option C is correct.
Question 10
1 / -0

Which one of the following is produced when acetone is saturated with $$HCl$$ gas?

A
Acetone alcohol

B
Phorone

C
Mesityl oxide

D
Benzene

Solution