Chemistry Test

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Chemistry Test - 24

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Weekly Quiz Competition

Question 1
3 / -1

If an alkyl halide reacts with alcoholic ammonia in a sealed tube, the product formed will be

A
a primary amine

B
a secondary amine

C
a tertiary amine

D
a mixture of all the three

Solution

In this case, the product will be a mixture of primary, secondary and tertiary amines.
Question 2
3 / -1

C-H bond energy is about 101 kcal/mol for methane, ethane and other alkanes, but is only 77 kcal/mol for C-H bond of CH₃ in toluene. This is because

A
of inductive effect due to – CH₃ in toluene

B
of the presence of benzene ring in toluene

C
of resonance among the structures of benzyl radical in toluene

D
of aromaticity of toluene

Solution

The C- H bond-dissociation energy is about 101 kcal/mole for methane, ethane, and other alkanes, but is only 77 kcal/mole for toluene, as determined by Szware from its rate of pyrolysis and by Schissler and Stevenson by electron impact. The difference, 24 kcal/mole, can be attributed to the resonance stabilization of the benzyl radical that is produced by removing one hydrogen atom from the methyl group of toluene; this radical resonates among the several structures.
Question 3
3 / -1

The concentration of reactant changes from 0.06 mol L^-1to 0.05 mol L^-1 in 25 minutes. Calculate the average rate of reaction.

A
4 x 10^-4mol L^-1min^-1

B
- 4 x 10^-4mol L^-1 min^-1

C
0.04 mol L^-1 min^-1

D
- 0.04 mol L^-1 min^-1

Solution

This option is correct because, rate of reaction is given by, Rate = - (change in concentration of reactants) / time. ( 0.06 - 0.05) / 25 = 4 x 10^-4 mol L^-1 min ^-1. Hence this option is correct.
Question 4
3 / -1

For synthesis of 1-butene, CH3MgI should be treated with

A
propene

B
2-chloropropene

C
allyl chloride

D
ethyl chloride

Solution
Question 5
3 / -1

Thermite is a mixture of

A
CrO₃ and Al₂O₃

B
Fe₂O₃ and Al

C
Fe₂O₃and Al₂O₃

D
Al₂O₃ and Cr

Solution

Thermite is a pyrotechnic composition of metal powder and metal oxide that produces an exothermic oxidation-reduction reaction known as a thermite reaction. The most commonly used mixture is of iron oxide and aluminium.
Question 6
3 / -1

In amino acid synthesis, acetyl chloride is used in the protection of _______ group.

A
cyano

B
amine

C
nitro

D
amide

Solution

Acetyl chloride is a commonly used acetylation agent for the preparation of fine chemicals, agrochemicals and pharmaceuticals. In amino acid synthesis, acetyl chloride can be used to protect amine groups. Acetyl chloride is also used in the production of dyes, the determination of water in organic liquids and in the analysis of cholesterol, lipids and fatty acids.
Question 7
3 / -1

Which of the following group of elements are called chalcophiles?

A
Ni, Co, Os, Ir

B
Se, As, Zn, Cd

C
Rb, Sr, Ba,

D
none of these

Solution

Chalcophile elements concentrate in sulfides, such as Se, As, Zn, Cd.
Question 8
3 / -1

Addition of HCl to vinyl chloride gives 1,1–dichloroethane because of

A
inductive effect of Cl

B
restricted rotation around the double bond

C
mesomeric effect of Cl

D
None of these

Solution

During the addition of HCl to vinyl chloride carbocation is formed as an intermediate which is stabilised by mesomeric effect of Cl^-.
Question 9
3 / -1

Acetaldehyde gives orange coloured precipitate on treatment with

A
2, 4-DNP

B
NH₂OH

C
NaHSO₃

D
NaOH

Solution

Acetaldehyde gives orange coloured precipitate on treatment with 2, 4-DNP.
Question 10
3 / -1

Highly reactive metals (like K, Na, Ca, Mg, Al) are extracted by

A
reducing carbon

B
electrolysis of their molten chlorides or oxides

C
heating their sulphide ore in air

D
Both (1) and (2)

Solution

Highly reactive metals are extracted by the electrolysis of their molten chlorides or oxides.

For example, when molten sodium chloride is electrolysed, sodium metal is obtained on cathode and chlorine gas is obtained at anode.

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Chemistry Test - 24

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Chemistry Test - 24

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Question 1

a primary amine

a secondary amine

a tertiary amine

a mixture of all the three

Solution

Question 2

of inductive effect due to – CH3 in toluene

of the presence of benzene ring in toluene

of resonance among the structures of benzyl radical in toluene

of aromaticity of toluene

Solution

Question 3

4 x 10-4mol L-1min-1

- 4 x 10-4 mol L-1 min-1

0.04 mol L-1 min-1

- 0.04 mol L-1 min-1

Solution

Question 4

propene

2-chloropropene

allyl chloride

ethyl chloride

Solution

Question 5

CrO3 and Al2O3

Fe2O3 and Al

Fe2O3 and Al2O3

Al2O3 and Cr

Solution

Question 6

cyano

amine

nitro

amide

Solution

Question 7

Ni, Co, Os, Ir

Se, As, Zn, Cd

Rb, Sr, Ba,

none of these

Solution

Question 8

inductive effect of Cl

restricted rotation around the double bond

mesomeric effect of Cl

None of these

Solution

Question 9

2, 4-DNP

NH2OH

NaHSO3

NaOH

Solution

Question 10

reducing carbon

electrolysis of their molten chlorides or oxides

heating their sulphide ore in air

Both (1) and (2)

Solution

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of inductive effect due to – CH₃ in toluene

4 x 10^-4mol L^-1min^-1

- 4 x 10^-4mol L^-1 min^-1

0.04 mol L^-1 min^-1

- 0.04 mol L^-1 min^-1

CrO₃ and Al₂O₃

Fe₂O₃ and Al

Fe₂O₃and Al₂O₃

Al₂O₃ and Cr

NH₂OH

NaHSO₃