Q20P - Chemistry: Molecular Nature Of Matter And Change

Question

Are these statements true or false? Correct any that are false. 

1. Two $\mathit{\sigma }$bonds comprise a double bond.
2. A triple bond consists of one $\mathbf{\tau \tau }$ bond and two $\mathbf{\sigma }$bonds.
3. Bonds formed from atomic s orbitals are always $\mathbf{\sigma }$bonds.
4. A  $\mathbf{\tau \tau }$bond restricts rotation about the $\mathbf{\sigma }$-bond axis.
5. A $\mathbf{\tau \tau }$bond consists of two pairs of electrons.
6. End-to-end overlap results in a bond with electron density above and below the bond axis.

Step-by-Step Solution

Answer

1. Two  $\sigma$bonds comprise a double bond. false. 
2. A triple bond consists of one $\mathbf{\tau \tau }$ond and two $\sigma$bonds. true
3. Bonds formed from atomic s orbitals are always $\sigma$ bonds. True 
4. A $\mathrm{\tau \tau }$bond restricts rotation about the $\sigma$ bond axis true
5. A  $\mathbf{\tau \tau }$bond consists of two pairs of electrons. True
6. End-to-end overlap results in a bond with electron density above and below the bond axis. false

Step1: For two bonds comprise a double bond

A Sigma bond is the single bond present between two atoms. A pi bond is the double bond present between two atoms which consists of one sigma and the other is a pi bond. This means that a double bond consists of one sigma and one pi.

Step2: For a triple bond consists of one ττ bond and two σ bonds

A Sigma bond is the single bond present between two atoms. when the double bond is present between two atoms which consists of one sigma and the other is pi bond. When two atoms are bonded by a triple in which one is sigma and two pi bonds.

This means that a triple bond consists of one sigma and two pi.

Step3: For bonds formed from atomic s orbitals are always σ bonds

A Sigma bond is the single bond present between two atoms. when the double bond is present between two atoms which consists of one sigma and the other is pi bond. When two atoms are bonded by a triple in which one is sigma and two pi bonds bond is formed by end-to-end overlapping of an orbital.

This means that bonds formed from s orbitals are always sigma bonds.

Step4: For a bond restricts rotation about the σ -bond axis

As pi bonds are mutually perpendicular to sigma bond and it forms by the lateral overlapping which by rotation will break. While rotating pi bond will break.

Step5: For a bond consisting of two pairs of electrons

Electrons that are present in a pi bond are called pi-electron. These electrons are existing both above and below the plane as pi bonds are formed by lateral overlapping. Therefore, the pi bond is composed of two pairs of electrons.

Step 6: End-to-end overlap creates a bond with electron densities above and below the bond axis.

Sigma bond is formed by end-to-end overlapping of an orbital. While the pi bond is formed by lateral overlapping above and below the plane. End-to-end overlap results in a bond with electron density internuclear axis.