Question

How many $ \sigma $ and $ \pi $ bonds are present in $ HC\equiv C-CH=CH-C{{H}_{3}} $ ​?
A) $ 9\sigma ,4\pi $
B) $ 10\sigma ,3\pi $
C) $ 6\sigma ,6\pi $
D) $ 5\sigma ,5\pi $

Answer 1

Hint: A chemical bond is a long-term attraction between atoms, ions, or molecules that allows chemical compounds to form. Ionic bonds are formed by the electrostatic force of attraction between oppositely charged ions, whereas covalent bonds are formed by the sharing of electrons. Chemical bonds have a wide range of strength.

Complete answer:
Sigma bonds ( $ \sigma $ bonds) are the strongest form of covalent chemical bond in chemistry. They're made up of atomic orbitals that collide head-on. For diatomic molecules, sigma bonding is most easily described using the language and tools of symmetry groups. A -bond is symmetrical with regard to rotation about the bond axis in this formal method. Because of the direct overlap of orbitals, sigma bonds are the strongest form of covalent bonds, and the electrons in these bonds are frequently referred to as sigma electrons.
Pi bonds ( $ \pi $ bonds) in chemistry are covalent chemical bonds formed when two lobes of an orbital on one atom overlap two lobes of an orbital on another atom laterally. At a common nodal plane running across the two bound nuclei, each of these atomic orbitals has zero electron density. The pi bond molecular orbital has a nodal plane in the same plane. Pi bonds can occur in double and triple bonds, but they almost never form in single bonds. Pi bonds are formed when two regions of overlap of atomic orbitals come into contact. The sigma bonds are more diffuse than the pi bonds. Pi electrons are electrons in pi bonds that are occasionally referred to as such.
A single bond is usually a sigma bond, but a multiple bond is made up of one sigma bond plus pi or other bonds. One sigma plus one pi bond makes a double bond, while one sigma plus two pi bonds makes a triple bond.
In $ HC\equiv C-CH=CH-C{{H}_{3}} $

	Number	\[\sigma \]	\[\pi \]
Triple bond	1	1	2
Double bond	1	1	1
Single bond	8	8	0
Total		10	3

Hence option B is correct.

Note:
Head-on overlapping of atomic orbitals produces sigma bonds. The idea of sigma bonding is expanded to include bonding interactions when a single lobe of one orbital overlaps with a single lobe of another. Propane, for example, is made up of ten sigma bonds, one for each of the two C - C bonds and one for each of the eight C - H bonds.