Order these compounds in order of decreasing carbon–carbon bond length: HCCH, H₂CCH₂, H₃CCH₃.

Verified step by step guidance

1. Identify the type of carbon-carbon bond in each compound: HCCH has a triple bond, H_2CCH_2 has a double bond, and H_3CCH_3 has a single bond.
2. Recall that bond length is inversely related to bond order: the higher the bond order, the shorter the bond length.
3. Understand that a triple bond (HCCH) is shorter than a double bond (H_2CCH_2), which is shorter than a single bond (H_3CCH_3).
4. Arrange the compounds in order of decreasing bond length: start with the compound with the longest bond (single bond) and end with the shortest bond (triple bond).
5. The order of decreasing carbon-carbon bond length is: H_3CCH_3, H_2CCH_2, HCCH.

Key Concepts

Bond Length

Bond length is the distance between the nuclei of two bonded atoms. In general, bond lengths vary depending on the type of bond (single, double, or triple) and the atoms involved. Shorter bonds typically indicate stronger interactions, while longer bonds suggest weaker interactions. Understanding bond length is crucial for comparing the structural characteristics of different compounds.

Types of Carbon Bonds

Carbon can form single, double, or triple bonds with other carbon atoms. Single bonds (as in alkanes) are the longest and weakest, while triple bonds (as in alkynes) are the shortest and strongest. The type of bond significantly influences the physical properties of the compound, including bond length. Recognizing these differences is essential for ordering compounds based on their carbon–carbon bond lengths.

Hybridization

Hybridization is the concept of mixing atomic orbitals to form new hybrid orbitals that can accommodate bonding. In carbon compounds, sp, sp², and sp³ hybridizations correspond to triple, double, and single bonds, respectively. The hybridization state affects the geometry and bond lengths of the molecules. Understanding hybridization helps predict the bond lengths in the given compounds.