What is the Bond Angle in Ethyne?

S6-SA4-0282

Grade Level:

Class 10

AI/ML, Physics, Biotechnology, Space Technology, Chemistry, Engineering, Medicine

Definition

What is it?

The bond angle in ethyne (C2H2) is 180 degrees. This specific angle is formed because the carbon atoms in ethyne are sp hybridized, leading to a linear molecular geometry.

Simple Example

Quick Example

Imagine a straight line, like the path an auto-rickshaw takes on a long, empty road without any turns. If you measure the angle along that straight path, it's 180 degrees. Ethyne molecules have a similar 'straight line' arrangement for their atoms.

Worked Example

Step-by-Step

Let's find the bond angle in ethyne step-by-step:

1. First, identify the chemical formula of ethyne: C2H2.
---
2. Next, draw the Lewis structure for ethyne. Each carbon atom forms a triple bond with the other carbon atom and a single bond with a hydrogen atom.
H - C ≡ C - H
---
3. Now, determine the hybridization of each carbon atom. Each carbon atom in ethyne has two sigma bonds (one with H, one with C) and two pi bonds (part of the triple bond). This means each carbon atom has two electron domains.
---
4. For two electron domains, the hybridization is sp.
---
5. Molecules with sp hybridization and two electron domains around the central atom always adopt a linear geometry.
---
6. In a linear geometry, all atoms lie in a straight line.
---
7. The angle formed by atoms in a straight line is 180 degrees.
---
Answer: The bond angle in ethyne is 180 degrees.

Why It Matters

Understanding bond angles helps chemists design new medicines and materials with specific shapes. In Biotechnology, this knowledge is crucial for understanding how proteins fold. Engineers use it to create strong, stable structures at a molecular level for new technologies.

Common Mistakes

MISTAKE: Assuming ethyne has a bent or trigonal planar shape. | CORRECTION: Ethyne is linear because of sp hybridization, leading to a 180-degree bond angle.

MISTAKE: Confusing ethyne's bond angle with that of ethene (C2H4) or ethane (C2H6). | CORRECTION: Ethyne has a triple bond (sp hybridization, 180 degrees), ethene has a double bond (sp2 hybridization, 120 degrees), and ethane has single bonds (sp3 hybridization, 109.5 degrees). Each is different!

MISTAKE: Forgetting to count the electron domains correctly to determine hybridization. | CORRECTION: Remember that a triple bond counts as one electron domain, and a single bond also counts as one electron domain when determining hybridization.

Practice Questions

Try It Yourself

QUESTION: What is the hybridization of carbon atoms in ethyne? | ANSWER: sp hybridization

QUESTION: If a molecule has a linear geometry, what is its bond angle? | ANSWER: 180 degrees

QUESTION: Explain why the bond angle in ethyne is different from the bond angle in methane (CH4). | ANSWER: Ethyne has sp hybridized carbon atoms with a triple bond, leading to a linear geometry and a 180-degree bond angle. Methane has sp3 hybridized carbon atoms with only single bonds, leading to a tetrahedral geometry and a 109.5-degree bond angle.