Test: Chemical Bonding- 1 - Chemistry MCQ

• H₂​S molecule has an angular geometry because it has two lone pairs of electrons that make the molecule bend. The dipole moment is not zero.
• This is because sulfur is more electronegative than hydrogen, making the molecule slightly polar.

• NF₃​,NCl₃​,PH₃​ - They all have trigonal pyramidal geometry.
• They all have a lone pair of electrons on their central atom.
• Whereas BH_3​ does not have a lonee pair, and is planar.

• B₂H₆ is electrons deficient molecule because boron atom has thre half-flled orbits in excited state.
• In it two electrons of a B-H bond are involved in formation of three centre bond, these bonds are represented as dotted lines.
• The structure of B₂H₆ is represented as follows.

A covalent bond is a chemical bond that involves the sharing of electron pairs between atoms. Organic Compounds are made up through sharing electron pairs.

Hybridization: to find the no.of hybridized bonds, add the no. of lone pairs with the no.of neighbour atoms.
3l.p+2(iodine atoms)=5
So Hybridization of l₃​⁻ = sp3d 
Note: These are the hyb. numbers that represent the type of hybridization.

2∼sp

3∼sp²

4∼sp³

5∼sp³d

6∼sp³d<sup>2

lone pairs - 3
Shape - Linear with a bend angle of 180°. The lone pairs are arranged in a trigonal bipyramidal arrangement.</sup>

Ortho, Meta & Para Benzene are all the same. i.e benzene only so all the carbons are having the same kind of hybridization i.e sp² so, Option D is correct.

LiF (Lithium Fluoride) is an example of Ionic bond, as the formation takes place by transfer of electrons and not by sharing.

Lateral overlap along the X-axis between two d_zx orbitals leads to the formation of a Pi-bond.

Magnesium Oxide(MgO) is used to make linings for some furnaces. It is known as a refractory material - which just means that it is resistant to heat and retains its strength at very high temperatures.

Diamagnetism is a quantum mechanical effect that occurs in all materials; when it is the only contribution to the magnetism, the material is called diamagnetic.

Paramagnetism is a form of magnetism whereby some materials are weakly attracted by an externally applied magnetic field and form internal induced magnetic fields in the direction of the applied magnetic field.

So, only in the conversion of NO → NO+, the bond order has increased from 2.5 to 3 and the paramagnetic character has changed to diamagnetic.

In BH3

We know that,

Boron has three valence electron, so it is supposed to make 3 bond in a molecules with hybridization sp² as only S and two p are used in hybridization because last p orbital vacant.

• Carbonium ion methonium,  CH₅+ is produced by the addition of  H+ to CH₄. In CH₅+ three hydrogen atoms are in a plane and one above and one below the plane. 
  
• So its sp³d and the shape is trigonal bipyramid. 
• But this compound is considered a CH₃+ carbenium ion with a molecule of hydrogen interacting with the empty orbital in a
  3-center-2-electron bond.
• As the two hydrogen atoms in H2 are in continuously exchange positions with the three hydrogen atoms in the CH₃+ methonium CH₅+ is considered as a fluxional molecule. Due to the existence of CH₃+, this is sp²​ hybridised. 

Both Ionic and Covalent bond arise from the tendency of atoms to attain stable configuration of electrons.

The percentage of p-character in forming P-P bonds in P₄ molecule is: 75. In forming 
P₄ molecule, P atom uses sp³ hybrid orbitals. Thus, the p-character in hybrid orbitals is 75%.

The correct option is : a H₂O Explanation:H₂O shows maximum H-bonding because each H₂O molecule is linked to four H₂O molecules through H-bonds.

When BF₃ forms an adduct with ether, it has 4 bonds respectively bonded with Oxygen (of ether) nd 3 F atoms. Presence of 4 bonds to the central atom results in sp³ hybridization.

An allene is a compound in which one carbon atom has double bonds with each of its two adjacent carbon centres.

The central carbon atom of allene forms two sigma bonds and two pi bonds. The central carbon is sp-hybridized, and the two terminal carbon atoms are sp²-hybridized. The bond angle formed by the three carbon atoms is 180°, indicating linear geometry for the carbon atoms of allene.

Multicenter bonding is typically associated with compounds that exhibit bonding that cannot be explained by conventional two-center two-electron bonds. This often involves compounds with electron-deficient atoms or those that form hypervalent bonds.

Let's evaluate the options:

1. B2H6: Diborane (B2H6) is a classic example of a molecule with multicenter bonding. It has two bridging hydrogen atoms that are involved in three-center two-electron bonds, connecting two boron atoms. This is a well-known case of multicenter bonding.
2. CH6++: This is not a standard compound and seems hypothetical. Such a molecule would be highly unstable and could theoretically involve multicenter bonding, but it's not a commonly recognized species.
3. SF4: Sulfur tetrafluoride (SF4) is hypervalent and has 10 electrons around sulfur, but it does not involve multicenter bonding. The bonding in SF4 can be explained using standard two-center bonds.

Given that B2H6 clearly has multicenter bonding and the other options are either incorrect or ambiguous:

Correct Answer: 1. B2H6

Correct option is A) NO₃⁻,CO₃⁻²

Number of electrons in the compound is :

• NO₃⁻​= 32e−
• CO₃^-2 ​= 32e−
• ClO₃⁻​= 42e−
• SO₃⁻​= 41e−

Therefore, NO₃⁻​ and CO₃^-2​ are isoelectronic

The structures of both NO₃⁻​ and CO₃^-2

 is trigonal planar.

Therefore NO₃⁻ ​and CO₃^-2are isostructural also.