Hydrogen Test

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Hydrogen Test - 13

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Weekly Quiz Competition

Question 1
1 / -0

The correct statements among (a) to (d) are:
(a) saline hydrides produce $$H_{2}$$ gas when reacted with $$H_{2}O$$.
(b) Reaction of $$LiAlH_{4}$$ with $$BF_{3}$$ leads to $$B_{2}H_{6}$$.
(c) $$PH_{3}$$ and $$CH_{4}$$ are electron - rich and electron - precise hydrides, respectively.
(d) $$HF$$ and $$CH_{4}$$ are called as molecular hydrides.

A
(c) and (d) only

B
(a), (b) and (c) only

C
(a), (b), (c) and (d)

D
(a), (c) and (d) only

Solution

(a) $$\underset {Ionic\ hydride/ saline\ hydride}{\overset {\oplus}{M} \overset {\ominus}{H} + HOH} \rightarrow MOH + H_{2}$$

(b) $$4BF_{3} + 3LiAlH_{4}\rightarrow 2B_{2}H_{6} + 3LiF + 3AlF_{3}$$

(C) Ref, image.

(d) $$HF$$ and $$CH_{4}$$ are molecular hydride because they are covalent molecules.
Question 2
1 / -0

Very pure hydrogen $$(99.9\%)$$ can be made by which of the following processes?

A
Reaction of methane with steam

B
Mixing natural hydrocarbons of high molecular weight

C
Electrolysis of water

D
Reaction of salt like hydrides with water

Solution

Pure hydrogen can be obtained from the electrolysis of water.

Cathode (reduction): $$2H_2O_{(l)}+ 2e^− \rightarrow H_{2(g)} + 2 OH^−_{(aq)}$$

Anode (oxidation): $$4OH^−_{(aq)}\rightarrow O_{2(g)} + 2H_2O_{(l)} + 4e^−$$

Combining either half reaction pair yields the same overall decomposition of water into oxygen and hydrogen:

Overall reaction: $$2H_2O_{(l)} \rightarrow 2H_{2(g)} + O_{2(g)}$$

The number of hydrogen molecules produced is thus twice the number of oxygen molecules.
Question 3
1 / -0

The hydride that is not electron deficent is:

A
$$B_2H_6$$

B
$$AlH_3$$

C
$$SiH_4$$

D
$$GaH_3$$

Solution

(1) $$B_2H_6 :$$ Electron deficient

(2) $$AlH_3 :$$ Electron deficient

(3) $$SiH_4 : $$ Electron precise as it has octet configuration in Si.

(4) $$GaH_3 :$$ Electron deficient
Question 4
1 / -0

Hydrogen peroxide oxidises $$[Fe(CN)_6]^{4-}$$ to $$[Fe(CN)_6]^{3-}$$ in acidic medium but reduce $$[Fe(CN)_6]^{3-}$$ to $$[Fe(CN)_6]^{4-}$$ in alkaline medium. The other products formed are, respectively:

A
$$H_2O$$ and $$(H_2O + O_2)$$

B
$$H_2O $$ and $$(H_2O + OH^-)$$

C
$$(H_2O + O_2)$$ and $$H_2O$$

D
$$(H_2O + O_2)$$ and $$(H_2O + OH^-)$$

Solution

(i) $$[Fe^{+2}(CN)_6]^{4-} +H_2O_2 + 2H^+ \rightarrow [Fe^{+3}(CN)_6]^{3-} +2H_2O$$

(ii) $$[Fe^{+3}(CN)_6]^{3-} +H_2O_2 +2OH^- \rightarrow [Fe^{+2}(CN)_6]^{4-} +O_2 + 2H_2O$$

From the following reaction it is clear that option A is correct.
Question 5
1 / -0

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

A
$$\mathrm{H}_{2}$$ is removed through occlusion with Pd

B
$$CO$$ is oxidised to $$\mathrm{C}\mathrm{O}_{2}$$ with steam in the presence of a catalyst followed by absorption of $$\mathrm{C}\mathrm{O}_{2}$$ in alkali

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

D
$$CO$$ is removed by absorption in aqueous $$\mathrm{C}\mathrm{u}_{2}\mathrm{C}l_{2}$$ solution

Solution

Water and coal are made to react by passing steam over red hot coke at very high temperature, producing a mixture of carbon monoxide and hydrogen which is called water gas.
Carbon monoxide is converted into carbon dioxide by passing the water gas and excess steam over the catalyst iron (III) oxide and chromium (III) oxide at very high temperature.
Carbon monoxide is separated from hydrogen gas by passing it through water at a pressure of 30 atmospheres due to which carbon monoxide is absorbed in water unlike hydrogen gas.
Question 6
1 / -0

Which of the following combination will produce $$H_{2}$$ gas?

A
$$Au$$ metal and $$NaCN(aq)$$ in the presence of air

B
$$Cu$$ metal and $$conc. HNO_{3}$$

C
$$Fe$$ metal and $$conc.HNO_{3}$$

D
$$Zn$$ metal and $$NaOH(aq)$$

Solution

Zn metal and NaOH(aq) will produce hydrogen gas.
$$\displaystyle Zn +2NaOH \rightarrow Na_2ZnO_2 + H_2 \uparrow$$

Gold react with sodium cyanide, oxygen and water, but no hydrogen gas is obtained.
$$\displaystyle 4Au + 8NaCN + O_2 + 2H_2O \rightarrow 4Na[Au(CN)_2] + 4NaOH$$

Cu metal reacts with conc. nitric acid but no hydrgen gas is obtained.
$$\displaystyle Cu + 4HNO_3 \rightarrow Cu(NO_3)_2 + 2H_2O +2NO_2 \uparrow$$

Fe metal reacts with conc. nitric acid but no hydrgen gas is obtained.
$$\displaystyle Fe + 6HNO_3 \rightarrow Fe(NO_3)_3 + 3H_2O +3NO_2 \uparrow$$

Hence, the correct option is D.
Question 7
1 / -0

Assertion: The $$O-O$$ bond length in $$H_2O_2$$ is shorter than that of $$O_2F_2$$.
Reason: $$H_2O_2$$ is an ionic compound.

A
If both assertion and reason are true and the reason is a correct explanation of the assertion

B
If both assertion and reason are true but reason is not a correct explanation of the assertion

C
If the assertion is true but reason is false

D
If both the assertion and reason are false

E
If the assertion is false but the reason is true

Solution

$$H_{2}O_{2}$$ is a covalent compound. In $$O_{2}F_{2}, O - O$$ bond is shorter than in $$H_{2}O_{2}$$ due to higher electronegativity of $$F$$.
Question 8
1 / -0

Which of the following process is not used in the concentration of $$H_{2}O_{2}$$?

A
Distillation under reduced pressure

B
Evaporation on a water bath

C
Fractional crystallization

D
Sublimation

Solution

Sublimation is not involved in concentration of $$H_{2}O_{2}$$.
Concentration of Hydrogen peroxide involves the following steps:
1. Evaporation of solution to obtain $$30\%$$ solution.
2. Distillation under pressure to get $$90\%$$ pure solution.
3. Fractional Distillation to get $$100\%$$ pure $$H_{2}O_{2}$$.
Question 9
1 / -0

As oxygen is ______ soluble in water. Air dissolved in water contains a higher percentage of oxygen (30-35%) than ordinary air (21%).

A
less

B
more

C
not

D
none of these

Solution

Air dissolved in water contains higher percentage of oxygen because solubility of oxygen gas is more than nitrogen and other gases present in ordinary air. Since the size of oxygen molecules is such that it gets trapped in the vacant space of water molecules (formed due to hydrogen bonding).
Therefore option B is correct
Question 10
1 / -0

Which of the following gas is lightest?

A
Dihydrogen

B
Helium

C
Dinitrogen

D
Dioxygen

Solution

Dihydrogen $$(H_2)$$ is the lightest gas as it is having two atoms of hydrogen, its molecular weight would be approximately $$2$$. And remaining atoms are having more than two I.e., $$4, 28, 32$$ for $$He, N_2, O_2$$ respectively.

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Hydrogen Test - 13

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Hydrogen Test - 13

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Question 1

(c) and (d) only

(a), (b) and (c) only

(a), (b), (c) and (d)

(a), (c) and (d) only

Solution

Question 2

Reaction of methane with steam

Mixing natural hydrocarbons of high molecular weight

Electrolysis of water

Reaction of salt like hydrides with water

Solution

Question 3

$$B_2H_6$$

$$AlH_3$$

$$SiH_4$$

$$GaH_3$$

Solution

Question 4

$$H_2O$$ and $$(H_2O + O_2)$$

$$H_2O $$ and $$(H_2O + OH^-)$$

$$(H_2O + O_2)$$ and $$H_2O$$

$$(H_2O + O_2)$$ and $$(H_2O + OH^-)$$

Solution

Question 5

$$\mathrm{H}_{2}$$ is removed through occlusion with Pd

$$CO$$ is oxidised to $$\mathrm{C}\mathrm{O}_{2}$$ with steam in the presence of a catalyst followed by absorption of $$\mathrm{C}\mathrm{O}_{2}$$ in alkali

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

$$CO$$ is removed by absorption in aqueous $$\mathrm{C}\mathrm{u}_{2}\mathrm{C}l_{2}$$ solution

Solution

Question 6

$$Au$$ metal and $$NaCN(aq)$$ in the presence of air

$$Cu$$ metal and $$conc. HNO_{3}$$

$$Fe$$ metal and $$conc.HNO_{3}$$

$$Zn$$ metal and $$NaOH(aq)$$

Solution

Question 7

If both assertion and reason are true and the reason is a correct explanation of the assertion

If both assertion and reason are true but reason is not a correct explanation of the assertion

If the assertion is true but reason is false

If both the assertion and reason are false

If the assertion is false but the reason is true

Solution

Question 8

Distillation under reduced pressure

Evaporation on a water bath

Fractional crystallization

Sublimation

Solution

Question 9

less

more

not

none of these

Solution

Question 10

Dihydrogen

Helium

Dinitrogen

Dioxygen

Solution

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