Chemistry Test

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Chemistry Test - 8

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Weekly Quiz Competition

Question 1
1 / -0

Following reactions are taking place in a Galvanic cell,

\(Z n \rightarrow Z n^{2+}+2 e^{-} ; A g^{+}+e^{-} \rightarrow A g\)

Which of the given representations is the correct method of depicting the cell?

A

\(Z n_{(s)}|Z n_{(a q)}^{2+} \| A g_{(a q)}^{+}| A g_{(s)}\)

B

\(Z n^{2+}|Z n \| A g| A g^{+}\)

C

\(Z n_{(a q)}|Z n_{(s)}^{2+} \| A g_{(s)}^{+}| A g_{(a q)}\)

D

\(Z n_{(s)}|A g_{(a q)}^{+} \| Z n_{(a q)}^{2+}| A g_{(s)}\)

Solution

The representation of the Galvanic cell is done as below:

Oxidation (left part) || Reduction (right part).

Aqueous elements have to be near the salt bridge in the representation. One has to remember that, in an electrochemical cell, reduction occurs at cathode and oxidation occurs at the anode.

Here in this question, option (A) satisfies the representation rules and thus, is the correct answer.

\({Zn}+2 {Ag}^{+} \longrightarrow {Zn}^{2+}+2 {Ag}\) can be represented as:

\(Z n_{(s)}|Z n_{(a q)}^{2+} \| A g_{(a q)}^{+}| A g_{(s)}\)
Question 2
1 / -0

The ions \(\mathrm{Mg}^{+2}\) and \(\mathrm{PO}_{4}^{-3}\) combine to form compounds:

A
\(\mathrm{Mg}_{3}\left(\mathrm{PO}_{4}\right)_{2}\)

B
\(\mathrm{Mg}_{2}\left(\mathrm{PO}_{4}\right)_{2}\)

C
\(\mathrm{Mg}_{2}\left(\mathrm{PO}_{4}\right)_{3}\)

D
\(\mathrm{Mg}_{3}\left(\mathrm{PO}_{4}\right)_{3}\)

Solution

The ions \(\mathrm{Mg}^{+2}\) and \(\mathrm{PO}_{4}^{-3}\) combine to form compound \(\mathrm{Mg}_{3}\left(\mathrm{PO}_{4}\right)_{2}\)

Total charge on cation \(=3(2+)=+6\).

Total charge on anion \(=2(-3)=-6\).

Therefore,

Total charge on cation \(=\) Total charge on anion.
Question 3
1 / -0

Molecules: General formula. (n represents the number of carbon atoms in chain)

1. Aldehydes: \(C _{ n } H _{2 n } O\)

2. Carboxylic acids: \(C _{ n } H _{2 n } O _{2}\)

3. Cycloalkanes: \(C _{ n } H _{2 n }\)

4. Alkanes: \(C _{ n } H _{2 n +2}\)

Which of the above matching is correct? Choose from the options given below:

A
1 and 2 only

B
1 and 4 only

C
1, 2 and 4 only

D
All are correct

Solution

All the given options are correctly matched.

Aldehyde has \(C _{n} H _{2} O\) general formula. Example: Ethanal \(- C _{2} H _{4} O , n =2\)

Carboxylic acid has \(C _{n} H _{2 n} O _{2}\) general formula. Example: Propionic acid \(- C _{3} H _{6} O _{2}, n =3\)

Cycloalkane has \(C _{ n } H _{2 n }\) general formula. Example: Cyclobutane \(- C _{4} H _{8}, n =4\)

Alkane also has \(C _{n} H _{2 n +2}\) general formula. Example: Ethane \(- C _{2} H _{6}, n =2\)
Question 4
1 / -0

Which of the following oxidation state is common for all lanthanides?

A
+2

B
+3

C
+4

D
+5
Solution
\(+3\)oxidation state is common for all lanthanides.
- \([\mathrm{Xe}] 4 \mathrm{f}^{1-14} \mathrm{~5 d}^{0-1} \mathrm{~6 s}^{2}\) is the general configuration of Lanthanides.
- It may seem \(+2\) should be the common oxidation state but relative stability depends on other factors as well.
- Lanthanides most commonly shows \(+3\) oxidation state due to high hydration enthalpy than of \(+2\) oxidation state.
Question 5
1 / -0

Calculate the 'spin only' magnetic moment of \({M}^{2+}{ }_{\text {(aq) }}\) ion \(({Z}=27 )\).

A
\(5 {~BM}\)

B
\(3 {~BM}\)

C
\(4 {~BM}\)

D
\(6 {~BM}\)

Solution

Given that:

Atomic Number, \(({Z} )=27\)

The configuration will be:

\( [{Ar}] 3 {~d}^{7} 4 {~s}^{2}\)

\(\therefore {M}^{2+}=[{Ar}] 3 {~d}^{7}\)

\(3 {~d}^{7}:\)

i.e., 3 unpaired electrons,

\(\therefore {n}=3\)

We know that,

Magnetic moment is given by:

\( \sqrt{n(n+2)}=\mu\)

where, \(\mathrm{n}=\) total number of unpaired electron

\( \sqrt{3(3+2)}=\mu\)

\( \sqrt{15}=\mu\)

\(\mu =3.8\approx 4 {~BM}\)
Question 6
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Arrange the following sets of compounds in order of their increasing boiling points:

Pentan \(-1-\) ol, butan \(-1- ol\), butan \(-2- ol\), ethanol, propan - \(1- ol\), methanol

A
Methanol, ethanol, propan - \(1- ol\), butan - \(2- ol\), butan - \(1- ol\), pentan - \(1-ol\).

B
Propan - \(1-ol\), butan - \(2- ol\), butan - \(1-o l\), pentan - \(1- ol\), methanol, ethanol

C
Pentan - \(1-ol\), Methanol, ethanol, propan - \(1-ol\), butan - \(2- ol\), butan - \(1-ol\)

D
Butan - \(2-ol\), butan - \(1-ol\), pentan - \(1-0l\), methanol, ethanol, propan - \(1-ol\)

Solution

Boiling point is a Vanderwall forces \(\alpha\) Molecular weight. When the molecular weight is same like in case of butan - \(1-ol\) and butan - \(2-ol\), then boiling point increases as branching decreases. because with increase in branching, molecule occupies a spherical shape and surface are of contact decreases and hence boiling point decreases.

So, butan - \(2-ol\) will have lower boiling point than butan - \(1-ol\).
Question 7
1 / -0

\(C_{3}H_{9}N\) can have how many structural isomers?

A
2

B
3

C
4

D
5

Solution

C₃H₉N can have 4 structural isomers. And its isomers are
Question 8
1 / -0

Directions: These questions consist of two statements, each printed as Assertion and Reason. While answering these questions, you are required to choose any one of the following four responses.

Assertion : SN2 reaction of an optically active aryl halide with an aqueous solution of KOH always gives an alcohol with opposite sign of rotation.

Reason : SN2 reactions always proceed with inversion of configuration.

A
If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.

B
If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.

C
If the Assertion is correct but Reason is incorrect.

D
If both the Assertion and Reason are incorrect.

Solution

Assertion is false, because aryl halides do not undergo nucleophilic substitution under ordinary conditions. This is due to resonance, because of which the carbon– chlorine bond acquires partial double bond character, hence it becomes shorter and stronger and thus cannot be replaced by nucleophiles. However Reason is true.
Question 9
1 / -0

Which of the following ligands form a chelate?

A
Acetate

B
Oxalate

C
Cyanide

D
Ammonia

Solution

In chelation, ring formation occurs because two atoms from the same ligand coordinate with the metal atom. This cannot happen if the ligand is monodentate.

Oxalate is a bidentate ligand so it forms a chelate. It can coordinate with both of its negatively charged O atoms.

Acetate, cyanide and ammonia are monodentate ligands. They do not form chelates.

Question 10

1 / -0

Match various processes in surface chemistry from List 1 with their definition from:

List 1	List 2
A. Dissipation	1. Weak Vanderwalls forces exist between adsorbent and adsorbate
B. Absorption	2. if the adsorbed gas or liquid leaves the surface
C. Sorption	3. If gas or liquid molecules are uniformly distributed through out the interior
D. Physisorption	4. If both absorption and adsorption will occur

A-2, B-4, C-3, D-1

A-1, B-4, C-2, D-1

A-2, B-3, C-4, D-1

A-3, B-4, C-1, D-2

Solution

In surface chemistry,

1. Dissipation/ Desorption is the process of removing an adsorbed substance from a surface on which it is absorbed.

2. Absorption is a process in which the substance (adsorbate) is uniformly distributed throughout the bulk.

3. Sorption is a process where both the phenomenon of adsorption and absorption take place simultaneously.

4. Physisorption is a type of adsorption where weak Van der Waals forces act between the adsorbate and adsorbent.

Thus, the correct combination of an answer will be A-2, B-3, C-4, D-1

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Chemistry Test - 8

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Chemistry Test - 8

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Question 1

\(Z n_{(s)}|Z n_{(a q)}^{2+} \| A g_{(a q)}^{+}| A g_{(s)}\)

\(Z n^{2+}|Z n \| A g| A g^{+}\)

\(Z n_{(a q)}|Z n_{(s)}^{2+} \| A g_{(s)}^{+}| A g_{(a q)}\)

\(Z n_{(s)}|A g_{(a q)}^{+} \| Z n_{(a q)}^{2+}| A g_{(s)}\)

Solution

Question 2

\(\mathrm{Mg}_{3}\left(\mathrm{PO}_{4}\right)_{2}\)

\(\mathrm{Mg}_{2}\left(\mathrm{PO}_{4}\right)_{2}\)

\(\mathrm{Mg}_{2}\left(\mathrm{PO}_{4}\right)_{3}\)

\(\mathrm{Mg}_{3}\left(\mathrm{PO}_{4}\right)_{3}\)

Solution

Question 3

1 and 2 only

1 and 4 only

1, 2 and 4 only

All are correct

Solution

Question 4

+2

+3

+4

+5

Solution

Question 5

\(5 {~BM}\)

\(3 {~BM}\)

\(4 {~BM}\)

\(6 {~BM}\)

Solution

Question 6

Methanol, ethanol, propan - \(1- ol\), butan - \(2- ol\), butan - \(1- ol\), pentan - \(1-ol\).

Propan - \(1-ol\), butan - \(2- ol\), butan - \(1-o l\), pentan - \(1- ol\), methanol, ethanol

Pentan - \(1-ol\), Methanol, ethanol, propan - \(1-ol\), butan - \(2- ol\), butan - \(1-ol\)

Butan - \(2-ol\), butan - \(1-ol\), pentan - \(1-0l\), methanol, ethanol, propan - \(1-ol\)

Solution

Question 7

2

3

4

5

Solution

Question 8

If both Assertion and Reason are correct and the Reason is a correct explanation of the Assertion.

If both Assertion and Reason are correct but Reason is not a correct explanation of the Assertion.

If the Assertion is correct but Reason is incorrect.

If both the Assertion and Reason are incorrect.

Solution

Question 9

Acetate

Oxalate

Cyanide

Ammonia

Solution

Question 10

A-2, B-4, C-3, D-1

A-1, B-4, C-2, D-1

A-2, B-3, C-4, D-1

A-3, B-4, C-1, D-2

Solution

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