Chemistry - CHEMICAL BONDING Question with Solution | TestHub

ChemistryCHEMICAL BONDINGMiscellaneous/MixedEasy2 minPYQ_2020
ChemistryEasysingle choice

The Lewis structure of allene is


Which of the following statements correctly gives answers for all 3 parts:
(a) Is the molecule planar?
(b) Does 1, 3 - dichloro propadiene show geometrical isomerism?
(c) Is the molecule 1, 3 - dichloro propadiene polar?

Options:

Answer:
A
Solution:

Hybridization of central carbon is sp and two of its unhybridized p -orbitals are involved in π - bonding. Also p - orbitals at an atom are orthogonal (at 90 ο angle), the two π - bonds at central carbon are also orthogonal. Let these p - orbitals, involved in π - bonding, at central carbon be p y and p z, then

 



Hybridization at the terminal carbons are both sp 2 . The two p - orbitals involved in sp 2 hybridization are p x and p y at left terminal and p x and p z at right terminals. Therefore, the three s p 2 hybrid orbitals at left terminal carbon are in xy plane, while the same at right terminal carbon are in xz
plane. As a result, the two triangular planes at terminals are at right angles as shown below: 

      
The two H - C - H planes at terminals are perpendicular to each other. ( π - bonds are also perpendicular to each other.)
      Hence, (a) Molecule is non - planar. (b) It doesn't show geometrical isomerism because two H and chlorine are in different planes. (c) polar.

Stream:NTA_ABHYASSubject:ChemistryTopic:CHEMICAL BONDINGSubtopic:Miscellaneous/Mixed
2mℹ️ Source: PYQ_2020

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