Chemistry Test

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Chemistry Test - 16

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Weekly Quiz Competition

Question 1
1 / -0

A cricket ball of 0.5 kg is moving with a velocity of 100 m/sec. What is the wavelength associated with its motion?

A
1/100 cm

B
6.6 x 10^-34 m

C
1.32 x 10^-35 m

D
6.6 x 10^-28 m

Solution

Mass of cricket ball = 0.5 kg
Velocity of cricket ball = 100 m/s

$λ = \frac{h}{m v}$

$= \frac{6.626 \times 10^{- 36}}{0.5 \times 100}$

$= \frac{6.626 \times 10^{- 36}}{0.5}$

$= 13.252 \times 10^{- 36}$

$= 1.325 \times 10^{- 35} m$
Question 2
1 / -0

For the reaction Cl2 + 2I-→ I2 + 2Cl-, the initial concentration of I-was 0.20 mol L-1 and the concentration after 20 min was 0.18 mol L-1. The rate of formation of I2 in mol lit-1 would be

A
1 x 10^-3

B
5 x 10^-4

C
1 x 10^-4

D
2 x 10^-3

Solution
Question 3
1 / -0

When 1 F of electricity is passed through acidulated water, the volume of O₂ evolved is

A
11.2 dm³

B
5.6 dm³

C
22.4 dm³

D
1.0 dm3

Solution

Write balance reaction for electrolysis of water and use Faraday's law and mole concept.

$2 H_{2} O ⇋ 4 H^{+} + 2 O^{2 -}$

At cathode, $4 H^{+} + 4 e^{-} \to 2 H_{2}$

At anode, $20^{2 -} - 4^{e -} \to O_{2}$

$∴$ 4 faraday of charge liberates = 1 mol
$= 22.4 d m^{3} O_{2}$

$∴$ 1 faraday of charge liberates $= \frac{22.4}{4} \times 1$

$= 5.6 d m^{3} O_{2}$
Question 4
1 / -0

At equilibrium of N2O4(g) ⇌ 2NO2(g), the observed molecular weight of N2O4 is 80 g mol-1 at 350 K. The percentage of dissociation of N2O4(g) at 350K is

A
10%

B
15%

C
20%

D
18%

Solution
Question 5
1 / -0

The solubility of CaF2 in pure water is 2.3 x 10-4 mol dm-3. Its solubility product will be

A
4.6 x 10^-4

B
4.6 x 10^-8

C
6.9 x 10^-12

D
4.9 x 10^-11

Solution
Question 6
1 / -0

_______ acts as a Lewis acid, but not as a Bronsted acid.

A
NH₂^-

B
O^2-

C
BF₃

D
OH-

Solution

Bronsted acids are substances which can donate protons.
Question 7
1 / -0

The coagulation of 200 mL of a positive colloid took place when 0.73 g HCl was added to it without changing the volume. The flocculation value of HCl for the colloid is

A
0.365 millimole

B
36.5 millimoles

C
100 millimoles

D
150 millimoles

Solution

Molarity $= \frac{0.73}{36.5} \times \frac{1000}{200} = 0.1 M$

This means that a minimum of 0.1 mole or 0.1 $\times$ 1000=100 millimoles are required for coagulating 1 L of colloid.
Question 8
1 / -0

The dissolution of sulphuric acid in water will exhibit

A
negative deviation from ideal behaviour

B
positive deviation from ideal behaviour

C
ideal behaviour

D
negative or positive deviation depending upon the mass of H2SO4dissolved

Solution

The forces of attraction between solute and solvent are larger than those existing in solute-solute and solvent-solvent. The solution thus exhibits negative deviation from ideal behaviour.
Question 9
1 / -0

How many moles of magnesium phosphate Mg3(PO4)2will contain 0.25 moles of oxygen atoms?

A
2.15 x 0.02

B
3.125 x 10^-2

C
1.25 x 10^-2

D
2. 5 x 10^-2

Solution

In $M g_{3} {(P O_{4})}_{2}$ one molecule of it contains 8 atoms of oxygen

$∵$ 8 moles of oxygen atoms are present in 1 mole $M g_{3} {(P O_{4})}_{2 .}$

$∴$ 0.25 mole of oxygen atoms are present in,

$\frac{0.25}{8} = 3.125 \times 10^{- 2}$ moles of $M g_{3} {(P O_{4})}_{2}$
Question 10
1 / -0

Which of the following coordination compounds would exhibit optical isomerism?

A
Pentaamminenitrocobalt(III) iodide

B
Diamminedichloroplatinum(II)

C
Trans-dicyanobis (ethylenediamine) chromium(III) chloride

D
Tris-(ethylenediamine) cobalt(III) bromide

Solution

Among all only Tris-(ethylenediamine) cobalt(III) bromide is unsymmetric and so they show optical isomerism.

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Chemistry Test - 16

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Chemistry Test - 16

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Question 1

1/100 cm

6.6 x 10-34 m

1.32 x 10-35 m

6.6 x 10-28 m

Solution

Question 2

1 x 10-3

5 x 10-4

1 x 10-4

2 x 10-3

Solution

Question 3

11.2 dm3

5.6 dm3

22.4 dm3

1.0 dm3

Solution

Question 4

10%

15%

20%

18%

Solution

Question 5

4.6 x 10-4

4.6 x 10-8

6.9 x 10-12

4.9 x 10-11

Solution

Question 6

NH2-

O2-

BF3

OH-

Solution

Question 7

0.365 millimole

36.5 millimoles

100 millimoles

150 millimoles

Solution

Question 8

negative deviation from ideal behaviour

positive deviation from ideal behaviour

ideal behaviour

negative or positive deviation depending upon the mass of H2SO4dissolved

Solution

Question 9

2.15 x 0.02

3.125 x 10-2

1.25 x 10-2

2. 5 x 10-2

Solution

Question 10

Pentaamminenitrocobalt(III) iodide

Diamminedichloroplatinum(II)

Trans-dicyanobis (ethylenediamine) chromium(III) chloride

Tris-(ethylenediamine) cobalt(III) bromide

Solution

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6.6 x 10^-34 m

1.32 x 10^-35 m

6.6 x 10^-28 m

1 x 10^-3

5 x 10^-4

1 x 10^-4

2 x 10^-3

11.2 dm³

5.6 dm³

22.4 dm³

4.6 x 10^-4

4.6 x 10^-8

6.9 x 10^-12

4.9 x 10^-11

NH₂^-

O^2-

BF₃

3.125 x 10^-2

1.25 x 10^-2

2. 5 x 10^-2