Question

What is the approximate bond angle around the central carbon atom in acrolein?

Answer 1

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The approximate bond angle around the central carbon atom in acrolein is 120°

The structure of acrolein is shown in the figure below. From the structure, we can deduce that the central carbon atom is in an sp2 hybridization (Atoms with a double bond hybridize in an sp2 fashion).

Atoms with sp2 hybridization have trigonal planar geometry, in this kind of hybridization, bonds are oriented the farthest away possible from each other, to minimize overlapping and the angle that allows that is 120°. 

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Answer 2

All three carbon atom has ${\mathbf{s}}{{\mathbf{p}}^{\mathbf{2}}}$ hybridization and therefore bond angle of all central atoms is approximately equal to $\boxed{{\mathbf{120^\circ }}}$.

Further Explanation:

Prediction of hybridization:

The hybridization can be determined by calculating the number of hybrid orbitals (X) which is formed by the atom. The formula to calculate the number of hybrid orbitals (X) as follows:

Steric number (X) = [(Number of atoms bonded to the central atom) + (Number of lone pairs on the central atom)]

Generally, the least electronegative atom is considered as the central atom. Calculate hybridization as follows:

1. If the value of X is 2 then it means two hybrid orbitals are to be formed and thus the hybridization is sp.

2. If the value of X is 3 then it means three hybrid orbitals are to be formed and thus the hybridization is $s{p^2}$.

3. If the value of X is 4 then it means four hybrid orbitals are to be formed and thus the hybridization is$s{p^3}$.

4. If the value of X is 5 then it means five hybrid orbitals are to be formed and thus the hybridization is $s{p^3}d$.

5. If the value of X is 6 then it means six hybrid orbitals are to be formed and thus the hybridization is $s{p^3}{d^2}$.

For carbon atom 1 (refer to the image attached):

Substitute 3 for a number of atoms bonded to the carbon atom and 0 for a number of lone pair on the central atom in equation (1) to find out the steric number.

$\begin{aligned}{\text{Steric number}}&=3 + 0\\&=3\\\end{aligned}$

The steric number of carbon atom 1 is 3 thus the hybridization of carbon atom 1 in acrolein is ${\mathbf{s}}{{\mathbf{p}}^{\mathbf{2}}}$.

For carbon atom 2 (refer to the image attached):  

Substitute 3 for a number of atoms bonded to the carbon atom and 0 for a number of lone pair on the central atom in equation (1) to find out the steric number.

$\begin{aligned}{\text{Steric number}}&=3 + 0\\&=3\ \end{aligned}$

The steric number of carbon atom 2 is 3 thus the hybridization of carbon atom 2 in acrolein is ${\mathbf{s}}{{\mathbf{p}}^{\mathbf{2}}}$.

For carbon atom 3 (refer to the image attached):  

Substitute 3 for a number of atoms bonded to the carbon atom and 0 for a number of lone pair on the central atom in equation (1) to find out the steric number.

$\begin{aligned}{\text{Steric number}}&=3 + 0\\&=3\\\end{aligned}$

The steric number of carbon atom 3 is 3 thus the hybridization of carbon atom 3 in acrolein is ${\mathbf{s}}{{\mathbf{p}}^{\mathbf{2}}}$.

Since all three carbon atom has ${\mathbf{s}}{{\mathbf{p}}^{\mathbf{2}}}$  hybridization and therefore, bond angle of all central atoms is approximately equal to ${\mathbf{120^\circ }}$.

Learn more:

1. Molecular shape around the central atom in the amino acid glycine: https://brainly.com/question/4341225

2. Component of John Dalton’s atomic theory:https://brainly.com/question/2357175

Answer details:

Grade: Senior School

Subject: Chemistry

Chapter: Covalent bonding and molecular structure

Keywords: hybridization, acrolein, geometry, sp2, steric number, 3, p orbital, s orbital, Lewis structure, hybridization of acrolein, central atom, carbon, hydrogen, oxygen, shape, double bond.