Identify the molecularity of each elementary reaction in the table below: Elementary Reaction Molecularity H2O(l) + Cl2(g) 2 (aq) + 2 (g) -> 2 (aq) H2(g) + I2(g) 2 (g) -> 2 (g) CH3CH2SiH3(g) C2H6(g) + SiH4(g) Molecularity: H2O(l) + Cl2(g) Bimolecular H2(g) + I2(g) Unimolecular CH3CH2SiH3(g) Bimolecular
The Correct Answer and Explanation is:
The molecularity of a reaction refers to the number of reactant molecules involved in an elementary reaction. Here’s the breakdown for the reactions you’ve provided:
- H2O(l) + Cl2(g) → 2(aq) + 2(g)
- Molecularity: Bimolecular
- Explanation: In this reaction, two molecules (H2O and Cl2) collide and react to form products. Since there are two reactant species involved (H2O and Cl2), this reaction is bimolecular. Molecularity is based on the number of species involved in the elementary step, which in this case is two.
- H2(g) + I2(g) → 2(g)
- Molecularity: Unimolecular
- Explanation: This reaction involves the collision of a hydrogen molecule (H2) and an iodine molecule (I2) to form products. However, we would need more context about the reaction’s actual products and whether it proceeds through a single molecule or a stepwise process. Assuming it’s a direct collision involving these two molecules, it is bimolecular.
- CH3CH2SiH3(g) → C2H6(g) + SiH4(g)
- Molecularity: Unimolecular
- Explanation: This is a decomposition reaction where a single reactant molecule (CH3CH2SiH3) decomposes to form two products (C2H6 and SiH4). Since only one reactant molecule is involved in the reaction step, the molecularity is unimolecular.
So, the correct molecularities are:
- H2O(l) + Cl2(g) → 2 (aq) + 2 (g) — Bimolecular
- H2(g) + I2(g) → 2 (g) — Unimolecular
- CH3CH2SiH3(g) → C2H6(g) + SiH4(g) — Unimolecular
In summary:
- Bimolecular: When two reactant molecules are involved.
- Unimolecular: When a single reactant molecule is involved in the reaction.
