p-Block Elements — Page 8 | JEE Chemistry

Q71

Match with : Name of oxo acid Oxidation state of 'P'

List - I		List - II
(a)	Hypophosphorous acid	(i)	+5
(b)	Orthophosphoric acid	(ii)	+4
(c)	Hypophosphoric acid	(iii)	+3
(d)	Orthophosphorous acid	(iv)	+2
()		(v)	+1

A (a) - (iv), (b) - (v), (c) - (ii), (d) - (iii)

B (a) - (iv), (b) - (i), (c) - (ii), (d) - (iii)

C (a) - (v), (b) - (i), (c) - (ii), (d) - (iii)

D (a) - (v), (b) - (iv), (c) - (ii), (d) - (iii)

Correct Answer

Option C

Solution

(a) Hypophosphorus acid :

{H_3}\underline P {O_2}

(+1) 3 + x + (–2)2 = 0 x = +1 (b) Orthophosphoric acid :

{H_3}\underline P {O_4}

(+1) 3 + x + (–2)4 = 0 x = +5 (c) Hypophosphoric acid :

{H_4}\underline {{P_2}} {O_6}

(+1) 4 + 2x + (–2)6 = 0 x = +4 (d) Orthophosphorous acid :

{H_3}\underline P {O_3}

(+1)3 + x + (–2)3 = 0 x = +3

Q72

The INCORRECT statement regarding the structure of C60 is :

A The five-membered rings are fused only to six-membered rings.

B It contains 12 six-membered rings and 24 five-membered rings.

C Each carbon atom forms three sigma bonds.

D The six-membered rings are fused to both six and five-membered rings.

Correct Answer

Option B

Solution

C60 molecule contains 20 five-membered rings and twelve six-membered rings All carbon atoms are equal & they undergo sp2 hybridisation.

Each carbon atom form a 3 sigma bond with the other 3 carbon atoms.

Q73

Match with (process) (catalyst)

List - I		List - II
(a)	Deacron's process	(i)	ZSM-5
(b)	Contact process	(ii)	$CuC{l_2}$
(c)	Cracking of hydrocarbons	(iii)	Particles 'Ni'
(d)	Hydrogenation of vegetable oils	(iv)	${V_2}{O_5}$ Choose the most appropriate answer from the options given below :

A (a)-(ii), (b)-(iv), (c)-(i), (d)-(iii)

B (a)-(i), (b)-(iii), (c)-(ii), (d)-(iv)

C (a)-(iii), (b)-(i), (c)-(iv), (d)-(ii)

D (a)-(iv), (b)-(ii), (c)-(i), (d)-(iii)

Correct Answer

Option A

Solution

In manufacture of H2SO4 (contact process), V2O5 is used as a catalyst.

Ni catalysts enables the hydrogenation of fats.

CuCl2 is used as catalyst in Deacon's process.

ZSM-5 used as catalyst in cracking of hydrocarbons.

Q74

Given below are the statements about diborane (a) Diborane is prepared by the oxidation of NaBH4 with I2 (b) Each boron atom is in sp2 hybridized state (c) Diborane has one bridged 3 centre-2-electron bond (d) Diborane is a planar molecule The option with correct statements is :

A (c) and (d) only

B (a) only

C (c) only

D (a) and (b) only

Correct Answer

Option B

Solution

Diborane is prepared by the reaction of NaBH4 with I2.

2NaBH4 + I2 $\to$ B2H6 + 2NaI + H2 In diborane, 'B' is sp3 hybrid, it is Non-planar and two 3c-2e $-$ bonds are present.

Q75

Which one of the following group-15 hydride is the strongest reducing agent?

A AsH3

B BiH3

C PH3

D SbH3

Correct Answer

Option B

Solution

Among 15th group hydrides, BiH3 is strongest reducing agent.

Q76

Which one of the following compounds of Group-14 elements is not known?

A [GeCl6]2

-

B [Sn(OH)6]2

-

C [SiCl6]2

-

D [SiF6]2

-

Correct Answer

Option C

Solution

[SiCl6]2 $-$ does not exist due to steric crowding of surrounding atoms.

Q77

The product obtained from the electrolytic oxidation of acidified sulphate solutions, is :

A HSO

_4^ -

B HO3SOOSO3H

C HO2SOSO2H

D HO3SOSO3H

Correct Answer

Option B

Solution

Electrolysis of concentrated solution of acidified sulphate solution yields H2S2O8.

Q78

Given below are two statement : one is labelled as Assertion A and the other is labelled as Reason R. Assertion A : SO2(g) is absorbed to a large extent than H2(g) on activated charcoal. Reason R : SO2(g) has a higher critical temperature than H2(g). In the light of the above statements, choose the most appropriate answer from the options given below.

A Both A and R are correct but R is not the correct explanation of A.

B Both A and R are correct and R is the correct explanation of A.

C A is not correct but R is correct.

D A is correct but R is not correct.

Correct Answer

Option B

Solution

Gases having higher critical temperature absorb to a greater extent.

Q79

Sulphur dioxide is one of the components of polluted air. SO2 is also a major contributor to acid rain. The correct and complete reaction to represent acid rain caused by SO2 is :

A 2SO2 + O2

\to

2SO3

B SO2 + O3

\to

SO3 + O2

C SO2 + H2O2

\to

H2SO4

D 2SO2 + O2 + 2H2O

\to

2H2SO4

Correct Answer

Option D

Solution

2\text{SO}_{2} +\text{O}_{2} +\text{2H}_{2} \text{O} \longrightarrow \text{2H}_{2} \text{SO}_{4}

Acid rain occurs due to increased concentration of oxides of sulphur and Nitrogen.

Q80

Among the given oxides of nitrogen ; N2O, N2O3, N2O4 and N2O5, the number of compound/(s) having N - N bond is :

A 1

B 2

C 3

D 4

Correct Answer

Option C

Solution

$\mathrm{N}_{2} \mathrm{O}, \mathrm{N}_{2} \mathrm{O}_{3}$ and $\mathrm{N}_{2} \mathrm{O}_{4}$ contain $\mathrm{N}-\mathrm{N}$ bond