Basics of Organic Chemistry (GOC) — Page 4 | JEE Chemistry

Q31

The correct match between items I and II is : .tg .tg Item-I (Mixture) Item-II (Seperation method) (A) H2O : Sugar (P) Sublimation (B) H2O : Aniline (Q) Recrystallization (C) H2O : Toluene (R) Steam distillation (S) Differential extraction

A A

\to

(R); (B)

\to

(P); (C)

\to

(S)

B A

\to

(Q); (B)

\to

(R); (C)

\to

(S)

C A

\to

(Q); (B)

\to

(P); (C)

\to

(R)

D A

\to

(S); (B)

\to

(R); (C)

\to

(P)

Correct Answer

Option B

Solution

To find the correct match, let's understand what each separation method does : Sublimation : The process where a substance changes directly from a solid to a gas without passing through the liquid state.

This method is not applicable to any mixtures here as all components are either liquid or soluble in liquid.

Recrystallization : A method used to purify a solid.

The impure compound is dissolved in a hot solvent and then allowed to slowly crystallize out as the solution cools.

This could be used to separate sugar from water.

Steam Distillation : A separation process which consists in distilling water together with other volatile and non-volatile components.

This could be used to separate aniline from water as aniline has a higher boiling point.

Differential extraction : It's a method that is used to separate a substance from a mixture by using an extracting solvent.

This could be used to separate toluene from water as toluene is less polar and wouldn't dissolve well in water.

So, the correct match would be : A -> Q : Water and sugar can be separated by recrystallization.

B -> R : Water and aniline can be separated by steam distillation.

C -> S : Water and toluene can be separated by differential extraction.

So, the correct option is Option C : A $\to$ (Q); (B) $\to$ (R); (C) $\to$ (S)

Q32

Match with . .tg .tg (Mixture) (Purification Process)

List - I		List - II
(A)	Chloroform & Aniline	(I)	Steam distillation
(B)	Benzoic acid & Napthalene	(II)	Sublimation
(C)	Water & Aniline	(III)	Distillation
(D)	Napthalene & Sodium chloride	(IV)	Crystallisation

A (A) - (IV), (B) - (III), (C) - (I), (D) - (II)

B (A) - (III), (B) - (I), (C) - (IV), (D) - (II)

C (A) - (III), (B) - (IV), (C) - (II), (D) - (I)

D (A) - (III), (B) - (IV), (C) - (I), (D) - (II)

Correct Answer

Option D

Solution

(A) Chloroform + Aniline $\rightarrow$ (III) Distillation (B) Benzoic acid + Napthalene $\rightarrow$ (IV) Crystallisation (C) Water + Aniline $\rightarrow$ (I) Steam distillation (D) Napthalene + Sodium chloride $\rightarrow$ (II) Sublimation

Q33

The increasing order of nucleophilicity of the following nucleophiles is : (a) CH3CO2

-

(b) H2O (c) CH3SO3

-

(d)

\mathop O\limits^ - H

A (b) < (c) < (a) < (d)

B (b) < (c) < (d) < (a)

C (a) < (d) < (c) < (b)

D (d) < (a) < (c) < (b)

Correct Answer

Option A

Solution

When stability of nucleophile increases then nucleophilicity decreases.

Stability order : H2O > CH3SO3 $-$ > CH3CO2 $-$ >

\mathop O\limits^ - H

So Nucleophilicity order : H2O < CH3SO3 $-$ < CH3CO2 $-$ <

\mathop O\limits^ - H

Q34

In 3,3-dimethylhex-1-en-4-yne, there are _________

\mathrm{sp}^3

,_________

\mathrm{sp}^2

and_________ sp hybridised carbon atoms respectively.

A

4,2,2

B

2,4,2

C

3,3,2

D

2,2,4

Correct Answer

Option A

Solution

$4-\mathrm{sp}^3, 2-\mathrm{sp}^2, 2-\mathrm{sp}$

Q35

In the anion HCOO

-

the two carbon-oxygen bonds are found to be of equal length. What is the reason for it?

A The C = O bond is weaker than the C-O bond

B The anion HCOO- has two resonating structures

C The anion is obtained by removal of a proton from the acid molecule

D Electronic orbitals of carbon atom are hybridised

Correct Answer

Option B

Solution

The anion is

HCO{O^ - }

exists in following resonating structures And actual structure will be, Bond order of this anion =

{3 \over 2}

= 1.5. As 1.5 is exactly in the middle of 1 and 2 so, the bond length will be equal between all carbon and oxygen atom.

Q36

Which of the following does not show geometrical isomerism?

A 1,2-dichloro-1-pentene

B 1,3-dichloro-2-pentene

C 1,1-dichloro-1-pentene

D 1,4-dichloro-2-pentene

Correct Answer

Option C

Solution

does not show geometrical isomerism due to presence of two similar

Cl

atoms on the same

C

-atom. Geometrical isomerism is shown by compounds in which the groups/atoms attached to

C=C

are different.

Q37

The general formula CnH2nO2 could be for open chain

A carboxylic acids

B diols

C dialdehydes

D deketones

Correct Answer

Option A

Solution

{C_n}{H_{2n}}{O_2}

is general formula for carboxylic acid

Q38

Which one of the following conformation of cyclohexane is chiral?

A Twist boat

B Rigid

C Chair

D Boat

Correct Answer

Option A

Solution

Chiral conformation will not have plane of symmetry. Since twist boat does not have plane of symmetry it is chiral.

Q39

Which of the following has the shortest C-Cl bond?

A Cl–CH=CH–CH3

B Cl–CH=CH–NO2

C Cl–CH=CH–OCH3

D Cl–CH=CH2

Correct Answer

Option B

Solution

due to strong – R effect of – NO2 group and M effect of Cl, partial double bond character between C and Cl increases.

So shortest bond length.

Q40

A flask contains a mixture of isohexane and 3-methylpentane. One of the liquids boils at 63oC while the other boils at 60oC What is the best way to separate the two liquids and which one will be distilled out first ?

A fractional distillation, 3-methylpentane

B simple distillation, 3-methylpentane

C fractional distillation, isohexane

D simple distillation, isohexane

Correct Answer

Option C

Solution

Isohexane and 3 Methylpentane Having same molecular formula.

Isohexane boil at 60oC and 3-Methyl pentane boil at 63oC.

Both Having low Boiling point difference so Fractional distillation is useful for separation and Isohexane Having low Boiling point So comes out first.