Hydrogen — Page 9 | NEET Chemistry

Q81

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.

Q82

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.

Q83

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})

Q84

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.)

Q85

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}.

Q86

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)

Q87

If the boiling point of H2O is 373 K, the boiling point of H2S will be :

A greater than 300 K but less than 373 K

B equal to 373 K

C more than 373 K

D less than 300 K

Correct Answer

Option D

Solution

Boiling point of H2S < Boiling point of H2O Boiling point of H2S = 213 K

Q88

The temporary hardness of a water sample is due to compound X. Boiling this sample converts X to compound Y. X and Y, respectively, are :

A Mg(HCO3)2 and MgCO3

B Ca(HO3)2 and CaO

C Ca(HCO3)2 and Ca(OH)2

D Mg(HCO3)2 and Mg(OH)2

Correct Answer

Option D

Solution

Accoring to NCERT this is the right reaction Mg(HCO3)2

\overset{\Delta}\longrightarrow

Mg(OH)2 $\downarrow$ + CO2 $\uparrow$ + H2O But right reaction should be, Mg(HCO3)2

\overset{\Delta}\longrightarrow

MgCO3 $\downarrow$ + CO2 $\uparrow$ + H2O

Q89

Match List I with List II .tg .tg LIST I Type of Hydride LIST II Example A. Electron deficient hydride I.

\mathrm{MgH_2}

B. Electron rich hydride II.

\mathrm{HF}

C. Electron precise hydride III.

\mathrm{B_2H_6}

D. Saline hydride IV.

\mathrm{CH_4}

Choose the correct answer from the options given below:

A A-III, B-II, C-I, D-IV

B A-II, B-III, C-I, D-IV

C A-III, B-II, C-IV, D-I

D A-II, B-III, C-IV, D-I

Correct Answer

Option C

Solution

A Electron deficient hydride -> III $\mathrm{B}_2 \mathrm{H}_6$ B Electron rich hydride -> II $\mathrm{HF}$ C Electron precise hydride -> IV $\mathrm{CH}_4$ D Saline hydride -> I $\mathrm{MgH}_2$

Q90

The volume strength of 1M H2O2 is : (Molar mass of H2O2 = 34 g mol–1)

A 5.6

B 22.4

C 11.35

D 16.8

Correct Answer

Option C

Solution

At STP, Volume strength = 11.35 $\times$ Molarity $\therefore$ Volume strength of H2O2 = 11.35 $\times$ 1 = 11.35