Question

Which of the following statements is wrong? (1) In the formation of tau or banana bond in diborane, the number of clectrons and the number of atoms involved, respectively, are 2 and 3 . (2) The number of hydrogen bridge bonds in diboranc is 2 . (3) Mcthylation of diborane gives only tetramethyl diborane. (4) The orbital overlap in hydrogen bridge bond is \(s p^{2} s s p^{2}\)

Short answer

The orbital overlap in hydrogen bridge bond is (sp2)-s-(sp2) is wrong.

Step-by-step solution

Understand diborane structure and banana bonds

Diborane (B2H6) consists of two boron atoms and six hydrogen atoms. It has a unique structure with two bridging hydrogen atoms forming so-called 'banana bonds' or 'tau bonds'. These bonds involve 3 atoms (2 boron and 1 hydrogen) and 2 electrons.

Number of hydrogen bridge bonds in diborane

In diborane, there are two hydrogen bridge bonds. Each bridge bond involves one hydrogen atom forming bonds with two boron atoms. So the statement 'The number of hydrogen bridge bonds in diborane is 2' is correct.

Methylation of diborane

Methylation of diborane involves replacing hydrogen atoms with methyl groups (CH3). It can produce different compounds, not just tetramethyl diborane. So the statement 'Methylation of diborane gives only tetramethyl diborane' is not entirely correct.

Orbital overlap in hydrogen bridge bond

The correct description of the orbital overlap in the hydrogen bridge bond in diborane is that the orbitals involved are (sp3) orbitals. Therefore, the statement 'The orbital overlap in hydrogen bridge bond is (sp2)-s-(sp2)' is incorrect.

Identify the wrong statement

Based on the evaluation, the wrong statements are about methylation and orbital overlap. Since we need to identify one wrong statement and such option directly stated in step 4, we can conclude 'The orbital overlap in hydrogen bridge bond is (sp2)-s-(sp2)' is wrong.

Key concepts

tau bond

Diborane (B2H6) is a fascinating molecule because it contains unusual bonds called 'tau bonds' or 'banana bonds'. These bonds are formed between a boron atom, another boron atom, and a single hydrogen atom. Essentially, in one tau bond, three atoms (two boron and one hydrogen) share two electrons. This type of bonding is quite unique and differs from typical covalent bonds.
Most covalent bonds involve two atoms sharing electrons, but in a tau bond, these three atoms cooperatively share two electrons to maintain stability. This results in a bent shape, often visualized like a banana, hence the name. This interaction makes the structure of diborane one of a kind.

methylation of diborane

Methylation refers to the process of adding methyl groups (CH3) to a molecule. For diborane, methylation involves replacing its hydrogen atoms with methyl groups. The process isn't straightforward and can lead to various compounds, not just tetramethyl diborane.
Contrary to some statements, methylation of diborane does not exclusively produce tetramethyl diborane (B2(CH3)4). Other possible products can include dimethyl diborane (B2H4(CH3)2) or even mixed methyl derivatives. This diversity arises since methylation can happen at different positions and to varying extents on the diborane molecule.
Understanding this process is crucial for chemistry students, as it highlights the variability and complexity of chemical reactions and the factors influencing product distribution.

orbital overlap

Orbital overlap plays a vital role in the bonding within molecules. In the context of diborane, particularly for the hydrogen bridge bond, the orbital overlap is significant. The hydrogen bridge bonds in diborane involve the interaction of sp3 hybridized orbitals of boron with the 1s orbitals of hydrogen.
The correct description of the orbital overlap in diborane's hydrogen bridge bond is: \(sp3\text{-}s\text{-}sp3\). This notation signifies that the sp3 hybrid orbitals of boron overlap with the s-orbital of the hydrogen atom to create stable bonds. Misunderstandings in this area can lead to incorrect conclusions about molecular structure and bonding.
Remember, precise knowledge about orbital overlap is fundamental for predicting molecule behavior and reactivity. It's a foundational concept that extends to understanding advanced topics in chemistry.

hydrogen bridge bond

Diborane's structure features unique hydrogen bridge bonds. These bonds involve a hydrogen atom that forms a bridge between two boron atoms. In diborane, each boron atom forms these bridges by sharing electrons with the hydrogen atoms, giving rise to two hydrogen bridge bonds.
Explaining further, each hydrogen bridge bond is part of a pair that links the two boron atoms in B2H6. Unlike typical single or double bonds where each bond is localized between two atoms, these bridge bonds span three atoms, creating a triangular arrangement.
Understanding these hydrogen bridge bonds is essential because they show how molecules can bond in non-standard ways to achieve stability. These bonds are crucial for the stability and unique properties of diborane, providing an excellent example of bonding versatility in chemistry.