Chemistry Test 221

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Chemistry Test 221

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Weekly Quiz Competition

Question 1
4 / -1

The correct order of basicity is

A

B

C

D

Solution

(Aliphatic amines) Most basic due to +I effect of methyl group. Methoxy group is electron donating group and increase electron density by (+M) effect on NH₂ group.

−NO₂ group withdraws electron density from N of −NH₂ and decrease basic strength.

Most basic because NH₂ connected with sp³ C while in i,ii&iii Connected with sp² C & basic strength ∝ +M/+I basic strength NO₂ exert -M so least basic while -OCH₃ exert +M so more basic.

M effect is a stronger effect than the I effect.

Aliphatic amines are more basic than aromatic amines because in aliphatic amines lone pair of electrons on nitrogen is localized and easy to donate, while in aromatic amines lone pair of electrons on nitrogen atom is delocalized and participate in resonance.
Question 2
4 / -1

Acetamide is treated separately with the following reagents. Which one of these would give methylamine?

A
PCl₅

B
Br₂Br₂ and NaOH

C
P₄O₁₀

D
LiAlH₄

Solution

This is a case of Hofmann reaction

The Hofmann bromamide is the organic reaction of conversion of a primary amide to a primary amine with one fewer carbon atom.

CH₃CONH₂ + Br₂ + 4 NaOH → CH₃NH₂ + Na₂CO₃ + 2 NaBr + 2 H₂O
Question 3
4 / -1

The products obtained from the following chemical reactions are respectively

A
NaOH and XeO₃

B
HClO₃ and XeO₂F₂

C
NaClO₃ and XeOF,

D
None of these

Solution

Chlorine gas reacts with hot and concentrated sodium hydroxide to produce sodium chloride and sodium chlorate. In this reaction chlorine is disproportionated. It is a redox reaction.

The reactions are as follows:
Question 4
4 / -1

Which of the following represents the best method for converting a carboxylic acid to an aldehyde?

A
Convert the acid to an acid chloride, and react the acid chloride with water.

B
Reduce the acid with LiAlH₄.

C
Convert the acid to an acid chloride, and reduce the acid chloride with lithium aluminium tri(t-butoxy) hydride.

D
Convert the acid to an acid chloride, react the acid chloride with a Grignard reagent, and reduce the product with LiAlH₄.

Solution
Question 5
4 / -1

The carbonate of which of the following cation is insoluble in water?

A
Na⁺

B
Na^-

C
NH⁺₄

D
Ca²⁺

Solution

Alkali metal carbonates and ammonium carbonate are soluble in water.

All other carbonates are insoluble in water.
Question 6
4 / -1

In orthorhombic unit cell the value of a, b and c are respectively 4.2 Å, 8.6 Å and 8.3 Å8.3 Å. Given the molecular mass of the solute is 155 g155 g mol⁻¹ and density is 3.3 g/cc , the number of formula units per unit cell is (Report your answer by rounding up to nearest integer)

A
2

B
3

C
4

D
6

Solution
Question 7
4 / -1

Which one of the following reactions will yield 2-propanol? Choose the right answer from (I), (II), (III) and (IV)

A
I and II

B
II and III

C
III and I

D
II and IV

Solution

(I) In this reaction, alkene gives the electrophilic addition reaction. Alkene formed the carbocation in acidic medium. After that water will attack on the carbocation and formed the 2− 2-propanol as a product.

(II) In the reaction, Grignard reagent gives the nucleophilic addition reaction and formed the 2−propanol as a product.

(III) In this reaction also, Grignard reagent gives the nucleophilic addition reaction and formed the 1−1-propanol as a product.

(IV) In this reaction, alkene react with the KMnO₄ and formed the propan−1, 2−diol as a product.
Question 8
4 / -1

More number of oxidation states are exhibited by the actinoids than those by the Lanthanoids, the main reason being

A
More reactive nature of the actinoids than the Lanthanoids.

B
4f orbitals more diffused than the 5f orbitals

C
More energy difference between 5f and 6d than between 4f and 5d orbitals

D
Lesser energy difference between 5f and 6d than between 4f and 5d orbitals

Solution

Actinoids show different oxidation states such as +2, +3, +4, +5, +6 and +7. However, +3 oxidation state is most common among all the lanthanoids. The wide range of oxidation states of actinoids is attributed to the fact that the 5f ,6d and 7s energy levels are of comparable energies. Therefore, all these three subshells can participate.
Question 9
4 / -1

According to the kinetic theory of gases, between two successive collisions, a gas molecule travels

A
In a circular path

B
In a wavy path

C
In a straight line path

D
With an accelerated velocity

Solution

According to kinetic theory, the gas molecules are in a state of constant rapid motion in all possible directions colliding in a random manner with one another and with the walls of the container and between two successive collisions, molecules travel in a straight line path but show haphazard motion due to collisions.
Question 10
4 / -1

The correct IUPAC name for the following compound is

A
1-Ethoxy-1-ethyl-1-aminopropane

B
1-Ethoxy-1-amino-1-ethylpropane

C
1-Ethoxy-2-butanol

D
2-Ethoxybutan-2-amine

Solution

Its correct IUPAC name is 2-Ethoxybutan-2-amine

While writing the names of polyfunctional compounds, the principal functional group is indicated by adding the secondary suffix to the word root while the secondary functional groups are indicated by adding prefixes to the word root.