Hydrogen — Page 8 | JEE Chemistry

Q71

The equation that represents the water-gas shift reaction is :

A CO(g) + H2O(g)

\mathrel{\mathop{\kern0pt\longrightarrow} \limits_{Catalyst}^{673K}}

CO2(g) + H2(g)

B CH4(g) + H2O(g)

\mathrel{\mathop{\kern0pt\longrightarrow} \limits_{Ni}^{1270K}}

CO(g) + 3H2(g)

C C(s) + H2O(g)

\overset{{1270K}}\longrightarrow

CO(g) + H2(g)

D 2C(s) + O2(g) + 4N2(g)

\overset{{1273K}}\longrightarrow

2CO(g) + 4N2(g)

Correct Answer

Option A

Solution

(A) Water gas shift reaction CO(g) + H2O(g)

\mathrel{\mathop{\kern0pt\longrightarrow} \limits_{Catalyst}^{673K}}

CO2(g) + H2(g) (B) Water gas is produced by this reaction CH4(g) + H2O(g)

\mathrel{\mathop{\kern0pt\longrightarrow} \limits_{Ni}^{1270K}}

CO(g) + 3H2(g) (C) Water gas is produced by this reaction C(s) + H2O(g)

\overset{{1270K}}\longrightarrow

CO(g) + H2(g) (D) Producer gas is produced by this reaction 2C(s) + O2(g) + 4N2(g)

\overset{{1273K}}\longrightarrow

2CO(g) + 4N2(g)

Q72

Deuterium resembles hydrogen in properties but :

A reacts slower than hydrogen

B reacts vigorously than hydrogen

C reacts just as hydrogen

D emits

\beta

+ particles

Correct Answer

Option A

Solution

The bond dissociation energy of D2 is greater than H2 and therefore D2 reacts slower than H2.

Q73

The oxide that gives H2O2 most readily on treatment with H2O is :

A PbO2

B Na2O2

C SnO2

D BaO2 . 8H2O

Correct Answer

Option B

Solution

(a) PbO2 + 2H2O $\to$ Pb(OH)4 (b) Na2O2 + 2H2O $\to$ 2NaOH + H2O2 this reaction is possible at room temperature (c) SnO2 + 2H2O $\to$ Sn(OH)4 (d) Acidified BaO2 .

8H2O gives H2O2 after evaporation.

Q74

NaH is an example of :

A metallic hydride

B saline hydride

C electron-rich hydrid

D molecular hydride

Correct Answer

Option B

Solution

NaH is an example of ionic hydride which is also known as saline hydride.

Q75

Given below are two statements : Statement I : Permutit process is more efficient compared to the synthetic resin method for the softening of water. Statement II : Synthetic resin method results in the formation of soluble sodium salts. In the light of the above statements, choose the most appropriate answer from the options given below:

A Statement I is correct but Statement II is incorrect

B Both the Statements I and II are correct

C Both the Statements I and II are incorrect

D Statement I is incorrect but Statement II is correct

Correct Answer

Option C

Solution

I.

Synthetic resin is more efficient as cations as well as anions responsible for removal of permanent hardness.

II.

In synthetic resin method, cations and anions are removed in the form of ppt.

Hence, both statements are incorrect.

Q76

Given below are two statements. Statement I : Hydrogen peroxide can act as an oxidizing agent in both acidic and basic conditions. Statement II : Density of hydrogen peroxide at

298 \mathrm{~K}

is lower than that of

\mathrm{D}_{2} \mathrm{O}

. In the light of the above statements, choose the correct answer from the options given below.

A Both Statement I and Statement II are true.

B Both Statement I and Statement II are false.

C Statement I is true but Statement II is false.

D Statement I is false but Statement II is true.

Correct Answer

Option C

Solution

Density of $\mathrm{H}_{2} \mathrm{O}_{2}$ is more as compared to $\mathrm{D}_{2} \mathrm{O}$

\begin{aligned} &\mathrm{d}_{\mathrm{H}_{2} \mathrm{O}_{2}}=1.44 \mathrm{~g} / \mathrm{cc} \\\\ &\mathrm{d}_{\mathrm{D}_{2} \mathrm{O}}=1.106 \mathrm{~g} / \mathrm{cc} \end{aligned}

And hydrogen peroxide acts as an oxidising as well as reducing agent in both acidic and basic medium.

$\therefore$ Statement $\mathrm{I}$ is correct.

Q77

The starting material for convenient preparation of deuterated hydrogen peroxide (

\mathrm{D_{2}O_{2}}

) in :

A

\mathrm{BaO_{2}}

B 2-ethylanthraquinol

C

\mathrm{BaO}

D

\mathrm{K_{2}S_{2}O_{8}}

Correct Answer

Option D

Solution

$\mathrm{K}_2 \mathrm{~S}_2 \mathrm{O}_8$ is used in the laboratory preparation of $\mathrm{D}_2 \mathrm{O}_2$

\mathrm{K}_2 \mathrm{~S}_2 \mathrm{O}_8(\mathrm{~s})+2 \mathrm{D}_2 \mathrm{O}(\mathrm{l}) \rightarrow 2 \mathrm{KDSO}_4(\mathrm{aq})+\mathrm{D}_2 \mathrm{O}_2(\mathrm{l})

Q78

Which one of the following statements is incorrect?

A Atomic hydrogen is produced when H2 molecules at a high temperature are irradiated with UV radiation.

B At around 2000 K, the dissociation of dihydrogen into its atoms is nearly 8.1%

C Bond dissociation enthalpy of H2 is highest among diatomic gaseous molecules which contain a single bond.

D Dihydrogen is produced on reacting zinc with HCl as well as NaOH(aq).

Correct Answer

Option B

Solution

Atomic hydrogen is produced at high temperature in an electric are or under ultraviolet radiations.

The dissociation of dihydrogen at 2000 K is only 0.081%.

H-H bond dissociation enthalpy is highest for a single bond for any diatomic molecule.

Dihydrogen can be produced on reacting Zn with dil.

HCl as well as NaOH (aq.)

Q79

Which one of the following process will produce hard water?

A Saturation of water with MgCO3

B Saturation of water with CaSO4

C Addition of Na2SO4 to water

D Saturation of water with CaCO3

Correct Answer

Option B

Solution

Permanent hardness of water is due to chlorides and sulphates of calcium and magnesium i.e.

CaC{l_2},CaS{O_4},MgC{l_2}\,

and

\,\,MgS{O_4}.

Q80

The chemical nature of hydrogen peroxide is :

A Oxidising agent in acidic medium, but not in basic medium

B Oxidising and reducing agent in both acidic and basic medium

C Reducing agent in basic medium, but not in acidic medium

D Oxidising and reducing agent in acidic medium, but not in basic medium.

Correct Answer

Option B

Solution

H2O2 act as oxidising agent and reducing agent in acidic medium as well as basic medium.

H2O2 Act as oxidant : - H2O2 + 2H

^ \oplus

+ 2e $-$ $\to$ 2H2O (In acidic medium) H2O2 + 2e $-$ $\to$ 2OH $-$ (In basic medium) H2O2 Act as reductant : - H2O2 $\to$ 2H+ + O2 + 2e $-$ (In acidic medium) H2O2 + 2OH $-$ $\to$ 2H2O + O2 + 2e $-$ (In basic medium)