Chemistry Test

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Chemistry Test - 12

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Weekly Quiz Competition

Question 1
3 / -1

How many nearest neighbours does Zn²⁺ ion have in zinc blend?

A
12

B
6

C
8

D
3

Solution

Next, the nearest neighbour of Zn⁺² would be = no of nearest surrounded Zn²⁺ ions.
next nearest neighbour of S^2-would be = no of nearest S^2-ions = 12 (due to FCC) and their number of the neighbour ratio is 1: 1 and that makes Zn²⁺ neighbour are 12.
Question 2
3 / -1

Which is the most suitable carrier gas in gas chromatography?

A
Helium

B
Nitrogen

C
Oxygen

D
Carbon dioxide

Solution

In gas chromatography, the carrier gas should be an inert gas which does not react with the sample. Even though nitrogen and some other gases are also used, \(90 \%\) of the instruments use helium as the carrier gas. Hydrogen is preferred for improved separations.
Question 3
3 / -1

Which type of amine is produced by reaction of ketones with primary amines, followed by reduction?

A
Secondary Aromatic amine

B
N-substituted amine

C
N, N-disubstituted amine

D
Primary aromatic amine

Solution

N‐substituted amines are produced by reaction of ketones with primary amines, followed by reduction.
\(CH_{3}-\overset{\overset{O}{\mid\mid}}{C}-CH_{3}\overset{1. CH_{3}NH_{2}}{\underset{2. H_{2}/Ni}{\longrightarrow}}-CH_{3}-\underset{\underset{H}{\mid}}{\overset{\overset{CH_{3}}{\mid}}{C}}-NHCH_{3}\)
Question 4
3 / -1

Under identical experiment conditions of the following pairs of gases will be most easy to separate by using effusion process:

A
\(\mathrm{H}_{2}\) and \(\mathrm{T}_{2}\)

B
\(\mathrm{SO}_{2}\) and \(\mathrm{SO}_{3}\)

C
\(\mathrm{NH}_{3}\) and \(CH_4\)

D
\(\mathrm{U}^{235} \mathrm{O}_{2}\) and \(\mathrm{U}^{238} \mathrm{O}_{2}\)

Solution

According to graham's law of diffusion,
Rate of effusion \(\propto \frac{1}{\sqrt{\text { molar mass }}}\)
Option (A):
Molar mass of \(\mathrm{H}_{2} = 4 + 4 = 8 \mathrm{~g}\)
Molar mass of \(\mathrm{T}_{2} = 48 + 48 = 96 \mathrm{~g}\)
Option (B):
Molar mass of \(\mathrm{SO}_{2} = 32 + 32 = 64 \mathrm{~g}\)
Molar mass of \(\mathrm{SO}_{3} = 32 + 48 = 80 \mathrm{~g}\)
Option (C):
Molar mass of \(\mathrm{CH}_{4}=12+4=16 \mathrm{~g}\)
Molar mass of \(\mathrm{NH}_{3}=14+3=17 \mathrm{~g}\)
Option (D):
Molar mass of \(\mathrm{U}^{235} \mathrm{O}_{2} = 235 + 32 = 267 \mathrm{~g}\)
Molar mass of \(\mathrm{U}^{238} \mathrm{O}_{2} = 238 + 32 = 270 \mathrm{~g}\)
All the option except \(\mathrm{H}_{2}\) and \(\mathrm{T}_{2}\) has nearly equal molar masses so separation become difficult but \(\mathrm{H}_{2}\) and \(\mathrm{T}_{2}\) has large difference in molar masses.
\(\mathrm{H}_{2}\) and \(\mathrm{T}_{2}\) has large difference in molar masses.
\(\therefore\) Separation with rates of effusion is possible.
Question 5
3 / -1

Which of the following structures represent the same stereoisomer?

A
Only 1 and 2

B
Only 2 and 3

C
1, 2 and 3

D
Only 3 and 1

Solution

To determine which of these structures are identical is to determine the configuration of each chirality center. In this case, for each chirality center the priority of the substituents is -Cl >; -CHClCH3 >; -CH3 >; -H.

For example, the configurations of the chirality centers of compound 1 are both S. However, 1 and 3 are not identical.
Question 6
3 / -1

In the reaction A → B, if the rate quadruples for every doubling of A, then what is the reaction order?

A
\(2\)

B
\(1\)

C
\(0\)

D
\(4\)

Solution

Rate \(=k[A][B]\) and Rate \(=k[A]^{2}\) are both second order reaction.
In the first case, \(A\) and \(B\) are both first order and in the second, \(A\) is second order.
If a reactant is second order, then when its concentration is doubled, the rate of the reaction quadruples \(\left(2^{2}=4\right)\).
If the concentration is tripled, the rate increases by a factor of \(9\left(3^{2}=9\right)\).
Question 7
3 / -1

Which of these is secondary pollutant?

A
\(\mathrm{CO}_{2}\)

B
\(\mathrm{SO}_{2}\)

C
\(\mathrm{O}_{3}\)

D
None of these

Solution

\(\mathrm{O}_{3}\) is a secondary pollutant whereas \(\mathrm{CO}_{2}\) and \(\mathrm{SO}_{2}\) are primary pollutants.
Secondary pollutants are not emitted directly. They are formed from the combination of primary pollutants with some other compound. Examples of secondary pollutants are Ozone, Formaldehyde, PAN (peroxy acetyl nitrate) and Smog etc.
Question 8
3 / -1

In context with the industrial preparation of hydrogen from water gas \(\left(\mathrm{CO}+\mathrm{H}_{2}\right)\), which of the following is the correct statement?

A
\(\mathrm{H}_{2}\) is removed through occlusion with \(\mathrm{Pd}\).

B
\(\mathrm{CO}\) is oxidized to \(\mathrm{CO}_{2}\) with steam in the presence of a catalyst followed by absorption of \(\mathrm{CO}_{2}\) in alkali.

C
\(\mathrm{CO}\) and \(\mathrm{H}_{2}\) are fractionally separated using differences in their densities.

D
\(\mathrm{CO}\) is removed by absorption in aqueous \(\mathrm{Cu}_{2} \mathrm{Cl}_{2}\) solution.

Solution

\(\mathrm{CO}\) is oxidized to \(\mathrm{CO}_{2}\) with steam in the presence of a catalyst followed by absorption of \(\mathrm{CO}_{2}\) in alkali.
\(\underbrace{C O+H_{2}}_{\text {Water gas }}+H_{2} O \stackrel{\text { Catalyst }}{\longrightarrow} \mathrm{CO}_{2}+2 \mathrm{H}_{2}\)
\(\mathrm{CO}_{2}+2 \mathrm{NaOH} \rightarrow \mathrm{Na}_{2} \mathrm{CO}_{3}+\mathrm{H}_{2} \mathrm{O}\)
Question 9
3 / -1

Which among the following reagents can be used for the test of carbonyl group in laboratory?

A

\(\mathrm{NH}_{2} \mathrm{OH}\)

B

\(\mathrm{NH}_{2} \mathrm{NH}_{2}\)

C
\(\mathrm{NH}_{2} \mathrm{NH}_{2}\) \(\mathrm{NaSO}_{3} \mathrm{H}\)

D

\(2,4-\mathrm{DNPH}\)

Solution

\(2,4-\mathrm{DNPH}\) is used for the test of carbonyl group in laboratory as a red coloured precipitate is formed:
Question 10
3 / -1

The pressure exerted by \(6 . 0~ g\) of methane gas in a \(0.03 \mathrm{~m}^{3}\) vessel at \(129^{\circ} \mathrm{C}\) is (Atomic masses \(: \mathrm{C}=12.01 \mathrm{H}=1.01\) and \(\left.\mathrm{R}=8.314 \mathrm{~J} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}\right):\)

A
\(215216 \mathrm{~Pa}\)

B
\(13409 \mathrm{~Pa}\)

C
\(41648 \mathrm{~Pa}\)

D
\(31684 \mathrm{~Pa}\)

Solution

Given:
Mass of \(\mathrm{CH}_{4}, \mathrm{m}=6 \mathrm{~g}\)
Volume of \(\mathrm{CH}_{4}, \mathrm{~V}=0.03 \mathrm{~m}^{3}\)
\(\mathrm{T}=129{ }^{\circ} \mathrm{C}=129+273=402 \mathrm{~K}\)
\(\mathrm{R}=8.314 \mathrm{~J} \mathrm{~K}^{-1} \mathrm{~mol}^{-1}\)
Molecular mass of \(\mathrm{CH}_{4}, \mathrm{M}=12.01+4.04\)
\(=16.05\)
From, ideal gas equation,
\(\mathrm{PV}=\mathrm{nRT}=\frac{\mathrm{m}}{\mathrm{M}} \mathrm{RT}\) [The chemical amount ( \(n\) ) (in moles) is equal to total mass of the gas \((m)\) (in kilograms) divided by the molar mass \((M)\) (in kilograms per mole):\(n=\frac{m}{M}\)]
\(\therefore \mathrm{P}=\frac{\mathrm{m}}{\mathrm{M}} \frac{\mathrm{RT}}{\mathrm{V}}\)
Put all the given values in above formula:
\(=\frac{6}{16.05} \times \frac{8.314 \times 402}{0.03}\)
\(=41647.7 \mathrm{~Pa} \approx 41648 \mathrm{P} \mathrm{a}\)

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Re-Attempt Weekly Quiz Competition

Chemistry Test - 12

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Chemistry Test - 12

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SHARING IS CARING

Question 1

12

6

8

3

Solution

Question 2

Helium

Nitrogen

Oxygen

Carbon dioxide

Solution

Question 3

Secondary Aromatic amine

N-substituted amine

N, N-disubstituted amine

Primary aromatic amine

Solution

Question 4

\(\mathrm{H}_{2}\) and \(\mathrm{T}_{2}\)

\(\mathrm{SO}_{2}\) and \(\mathrm{SO}_{3}\)

\(\mathrm{NH}_{3}\) and \(CH_4\)

\(\mathrm{U}^{235} \mathrm{O}_{2}\) and \(\mathrm{U}^{238} \mathrm{O}_{2}\)

Solution

Question 5

Only 1 and 2

Only 2 and 3

1, 2 and 3

Only 3 and 1

Solution

Question 6

\(2\)

\(1\)

\(0\)

\(4\)

Solution

Question 7

\(\mathrm{CO}_{2}\)

\(\mathrm{SO}_{2}\)

\(\mathrm{O}_{3}\)

None of these

Solution

Question 8

\(\mathrm{H}_{2}\) is removed through occlusion with \(\mathrm{Pd}\).

\(\mathrm{CO}\) is oxidized to \(\mathrm{CO}_{2}\) with steam in the presence of a catalyst followed by absorption of \(\mathrm{CO}_{2}\) in alkali.

\(\mathrm{CO}\) and \(\mathrm{H}_{2}\) are fractionally separated using differences in their densities.

\(\mathrm{CO}\) is removed by absorption in aqueous \(\mathrm{Cu}_{2} \mathrm{Cl}_{2}\) solution.

Solution

Question 9

\(\mathrm{NH}_{2} \mathrm{OH}\)

\(\mathrm{NH}_{2} \mathrm{NH}_{2}\)

\(\mathrm{NH}_{2} \mathrm{NH}_{2}\) \(\mathrm{NaSO}_{3} \mathrm{H}\)

\(2,4-\mathrm{DNPH}\)

Solution

Question 10

\(215216 \mathrm{~Pa}\)

\(13409 \mathrm{~Pa}\)

\(41648 \mathrm{~Pa}\)

\(31684 \mathrm{~Pa}\)

Solution

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