Delocalization of ${\rm{\pi }}$-electrons

Delocalization of ${\rm{\sigma }}$-electrons

Molecular size of ${\rm{ICl}}$ and ${\rm{B}}{{\rm{r}}_2}$ is nearly same, but boiling point of ${\rm{ICl}}$ is about $40^\circ C$ higher than ${\rm{B}}{{\rm{r}}_2}$. This might be due to:

${\rm{ICl}}$ is polar where as ${\rm{B}}{{\rm{r}}_2}$ is non-polar

${\rm{I - Cl}}$ bond is stronger than ${\rm{Br}} - {\rm{Br}}$ bond

Ionisation energy of ${\rm{I}} < $ ionisation energy of Br

The size of ${\rm{I}} > $ size of ${\rm{Br}}$

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Chemical bonding & molecular structure practice · Mixed difficulty

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511 Easy

511 of 579

Understanding +4 | -1

Resonance is due to:

View answer and explanation

Correct option: B

Delocalization of

\mathrm{\pi }

-electrons

Option B (Delocalization of

\mathrm{\pi }

-electrons) is correct because resonance involves the movement of pi electrons, not sigma electrons or atoms.

512 Medium

512 of 579

Remembering +4 | -1

In a crystal cations and anions are held together by

View answer and explanation

Correct option: B

Electrostatic forces

Option B (Electrostatic forces) is correct because cations and anions in a crystal are held together by electrostatic forces (ionic bonds).

513 Easy

513 of 579

Remembering +4 | -1

In ethene, the bond angle(s) is/are

View answer and explanation

Correct option: B

120^{\circ}

Option B (

120^{\circ}

) is correct because ethene (

C_2H_4

) has a trigonal planar geometry around each carbon atom due to

sp^2

hybridization, resulting in bond angles of approximately 120 degrees.

514 Medium

514 of 579

Understanding +4 | -1

Which has highest melting point?

View answer and explanation

Correct option: A

\mathrm{LiCl}

Option A (

\mathrm{LiCl}

) is correct because ionic compounds generally have higher melting points than covalent compounds, and LiCl has the most ionic character among the given options.

515 Hard

515 of 579

Analyzing +4 | -1

Among the following, the species with identical bond order are

View answer and explanation

Correct option: C

\mathrm{O}_2^{2-}

and

\mathrm{B}_2

Option C (

\mathrm{O}_2^{2-}

and

\mathrm{B}_2

) is correct because both species have a bond order of 1.

516 Easy

516 of 579

Analyzing +4 | -1

Which does not have pyramidal geometry?

View answer and explanation

Correct option: B

\mathrm{NO}_3^ -

Option B (

\mathrm{NO}_3^ -

) is correct because it has a trigonal planar geometry, not pyramidal.

517 Hard

517 of 579

Application +4 | -1

\mathrm{H} - X

bond length is

2.00 Å

and

\mathrm{H} - X

bond has dipole moment

5.12 \times {10^{ - 30}}\mathrm{C} - \mathrm{m}

, the percentage of ionic character in the molecule will be

View answer and explanation

Correct option: B

16\%

Option B is correct because the percentage of ionic character is calculated using the ratio of observed dipole moment to theoretical dipole moment.

518 Hard

518 of 579

Application +4 | -1

Total number of molecules/species from following which will be paramagnetic is ______.

\mathrm{O}_2,

\mathrm{O}_2^{+},

\mathrm{O}_2^{-},

\mathrm{NO},

\mathrm{NO}_2,

\mathrm{CO},

\mathrm{K}_2\left[\mathrm{NiCl}_4\right],

\left[\mathrm{Co}\left(\mathrm{NH}_3\right)_6\right] \mathrm{Cl}_3,

\mathrm{K}_2\left[\mathrm{Ni}(\mathrm{CN})_4\right]

View answer and explanation

Correct option: A

The correct answer is A (6) because the paramagnetic species are O2, O2+, O2-, NO, NO2, and [Co(NH3)6]Cl3.

519 Easy

519 of 579

Understanding +4 | -1

Formation of

\pi

-bond:

View answer and explanation

Correct option: B

Decreases bond length

Option B is correct because the formation of a

\pi

-bond adds electron density between the atoms, increasing the attraction and decreasing the bond length.

520 Easy

520 of 579

Application +4 | -1

Which of the following is a polar molecule

View answer and explanation

Correct option: A

S{F_4}

Option A (

S{F_4}

) is correct because it has a see-saw shape due to one lone pair, resulting in a net dipole moment.

521 Medium

521 of 579

Application +4 | -1

Which of the following has fractional bond order?

View answer and explanation

Correct option: D

\mathrm{H}_2^ -

Option D (

\mathrm{H}_2^ -

) is correct because it has a bond order of 0.5, which is a fractional bond order.

522 Medium

522 of 579

Remembering +4 | -1

According to Fajan's rule covalent bond is favoured by:

View answer and explanation

Correct option: A

Small cation and large anion

Option A (Small cation and large anion) is correct because, according to Fajan's rule, a small cation and a large anion favor covalent character due to increased polarization.

523 Medium

523 of 579

Understanding +4 | -1

proton plays an important role in…bonding.

View answer and explanation

Correct option: D

Coordinate

Option D (Coordinate) is correct because a proton (H+) accepts a lone pair of electrons from another atom to form a coordinate bond.

524 Hard

524 of 579

Application +4 | -1

The number of unpaired electrons in a paramagnetic diatomic molecule of an element with atomic number 16 is:

View answer and explanation

Correct option: C

Option C (2) is correct because an element with atomic number 16 (Sulfur) forms

O_2

which has 2 unpaired electrons.

525 Easy

525 of 579

Remembering +4 | -1

The bond angle in ethylene is

View answer and explanation

Correct option: B

120^{\circ}

Option B (

120^{\circ}

) is correct because ethylene (

C_2H_4

) has a double bond between the carbon atoms, resulting in

sp^2

hybridization and a trigonal planar geometry around each carbon with bond angles of 120 degrees.

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526 Medium

526 of 579

Remembering +4 | -1

According to Fajan's rule polarization is more when:

View answer and explanation

Correct option: A

Small cation and large anion

Option A (Small cation and large anion) is correct because according to Fajan's rule, polarization is favored by a small, highly charged cation and a large, highly charged anion.

527 Medium

527 of 579

Remembering +4 | -1

When hydrogen bond is formed between two molecules, it is called:

View answer and explanation

Correct option: B

intermolecular

{H}

-bond

Option B (intermolecular

{H}

-bond) is correct because hydrogen bonds formed between two separate molecules are called intermolecular hydrogen bonds.

528 Hard

528 of 579

Analyzing +4 | -1

The true statements from the following are
1.

\mathrm{P}{\mathrm{H}_5}

and

\mathrm{BiC}{\mathrm{l}_5}

do not exist
2.

p\pi - d\pi

bond is present in

\mathrm{S}{\mathrm{O}_2}

3.Electrons travel at the speed of light
4.

\mathrm{Se}{\mathrm{F}_4}

and

\mathrm{C}{\mathrm{H}_4}

have same shape
5.

\mathrm{I}_3^ +

has bent geometry

View answer and explanation

Correct option: B

1,2,5

Option B (1,2,5) is correct because

PH_5

and

BiCl_5

do not exist due to the inert pair effect and the inability of P to expand its octet,

SO_2

has

p\pi - d\pi

bonding, and

I_3^+

has a bent geometry.

529 Easy

529 of 579

Understanding +4 | -1

Which of the following is false?

View answer and explanation

Correct option: D

Alkyl halides have higher b.p. than corresponding alcohols

Option D (Alkyl halides have higher b.p. than corresponding alcohols) is correct because alcohols generally have higher boiling points than alkyl halides due to hydrogen bonding.

530 Medium

530 of 579

Application +4 | -1

Atoms

\mathrm{X}

and

\mathrm{Y}

combine to create an ionic compound with the formula

\mathrm{XY}_2.

Among the following options, which pair of atomic numbers for

\mathrm{X}

and

\mathrm{Y}

is suitable for this compound?

View answer and explanation

Correct option: C

\mathrm{X}=12 ; \mathrm{Y}=17

Option C (

\mathrm{X}=12 ; \mathrm{Y}=17

) is correct because X with 12 electrons (Magnesium) will lose 2 electrons to form

X^{2+}

, and Y with 17 electrons (Chlorine) will gain 1 electron to form

Y^{-}

. Thus, the formula

XY_2

is formed.

531 Medium

531 of 579

Understanding +4 | -1

A coordinate bond is a dative covalent bond. Which of the below is true?

View answer and explanation

Correct option: C

Two atoms form bond and one of them provides both electrons

Option C (Two atoms form bond and one of them provides both electrons) is correct because that is the definition of a coordinate covalent bond.

532 Easy

532 of 579

Analyzing +4 | -1

Which of the following pairs of species have identical shapes

View answer and explanation

Correct option: C

Xe{F_4}

and

ICl_4^ -

Option C (

Xe{F_4}

and

ICl_4^ -

) is correct because both have a square planar shape with 4 bond pairs and 2 lone pairs around the central atom.

533 Hard

533 of 579

Understanding +4 | -1

Which has the minimum bond energy?

View answer and explanation

Correct option: C

I - I

Option C (

I - I

) is correct because the bond energy decreases as the size of the atom increases due to increased bond length and weaker attraction.

534 Medium

534 of 579

Understanding +4 | -1

Molecular size of

\mathrm{ICl}

and

\mathrm{B}{\mathrm{r}_2}

is nearly same, but boiling point of

\mathrm{ICl}

is about

40^\circ C

higher than

\mathrm{B}{\mathrm{r}_2}

. This might be due to:

View answer and explanation

Correct option: C

\mathrm{ICl}

is polar where as

\mathrm{B}{\mathrm{r}_2}

is non-polar

Option C is correct because the higher boiling point of ICl compared to Br2 is due to the dipole-dipole interactions present in polar ICl molecules, which are absent in non-polar Br2 molecules.

535 Hard

535 of 579

Application +4 | -1

What is the formal charge on middle ‘

O

’ atom in ozone molecule?

View answer and explanation

Correct option: B

+1

Option B (+1) is correct because the formal charge on the central oxygen atom in ozone is +1.

536 Easy

536 of 579

Analyzing +4 | -1

In which of the following molecules / ions all the bonds are not equal

View answer and explanation

Correct option: B

S{F_4}

Option B (

S{F_4}

) is correct because it has a see-saw shape due to one lone pair, resulting in unequal bond lengths.

537 Easy

537 of 579

Application +4 | -1

A diatomic molecule has dipole moment of 1.2 D. If the bond distance is 1A, what percentage of electronic charge exists on each atom

View answer and explanation

Correct option: C

25\% \,of\,{e^ - }

Option C (

25\% \,of\,{e^ - }

) is correct because the percentage of electronic charge is calculated using the formula

\mu = q \times d

, where

\mu

is the dipole moment,

q

is the charge, and

d

is the bond distance.

538 Medium

538 of 579

Understanding +4 | -1

Shortest bond length among the following is of

View answer and explanation

Correct option: B

O – H

Option B (O – H) is correct because oxygen is more electronegative than carbon and nitrogen, leading to a smaller atomic radius and thus a shorter bond length.

539 Hard

539 of 579

Application +4 | -1

The electronegativity of

{H}

and

{Cl}

are 2.1 and 3.0 respectively. The correct statement(s) about the nature of

{HCl}

is/are:

View answer and explanation

Correct option: A

{HCl}

17 \%

ionic

Option A (

{HCl}

17 \%

ionic) is correct because the percentage ionic character can be estimated using the electronegativity difference between H and Cl.

540 Easy

540 of 579

Analyzing +4 | -1

Which of the following molecules has the maximum dipole moment

View answer and explanation

Correct option: C

N{H_3}

Option C (

N{H_3}

) is correct because

NH_3

has a pyramidal structure with a lone pair, resulting in a significant dipole moment due to the additive effect of bond dipoles and the lone pair dipole.

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