Chemical Bonding & Molecular Structure

Isostructural compounds are those that have the same shape and similar bond angles. To determine which compound is isostructural with carbon dioxide (CO₂), we need to analyze the molecular geometry of each of the options.

1. CO₂ has a linear structure with the carbon atom in the center, double-bonded to two oxygen atoms, giving it a bond angle of 180°. The structure can be represented as:

$ \text{O} = \text{C} = \text{O} $

2. HgCl₂ also has a linear structure. The mercury atom in the center is single-bonded to two chlorine atoms, giving it a bond angle of 180°. The structure can be represented as:

$ \text{Cl} - \text{Hg} - \text{Cl} $

3. SnCl₂ has a bent (or V-shaped) structure due to lone pairs on the tin atom. Hence, it is not isostructural with CO₂.

4. C₂H₂ (acetylene) has a linear structure with a carbon-carbon triple bond and hydrogen atoms at each end, giving it a bond angle of 180°. The structure can be represented as:

$ \text{H} - \text{C} \equiv \text{C} - \text{H} $

5. NO₂ has a bent structure due to the presence of a lone electron on the nitrogen atom, which causes repulsion and bends the molecule. Therefore, it is not isostructural with CO₂.

Given this analysis, CO₂ is isostructural with both HgCl₂ and C₂H₂.

The statement "SnCl₂ is a non-linear molecule" is TRUE.

To understand why SnCl₂ (Tin(II) chloride) is a non-linear molecule, we need to look at its molecular geometry. Tin (Sn) is the central atom and it has a lone pair of electrons along with two bonding pairs of electrons with the chlorine (Cl) atoms. This creates a V-shaped or bent molecular geometry.

According to the Valence Shell Electron Pair Repulsion (VSEPR) theory, the lone pair of electrons on the tin atom will repel the bonding pairs, causing the molecule to take on a shape that minimizes repulsion. Therefore, the electron geometry of SnCl₂ is trigonal planar, but because of the lone pair, the molecular shape is bent.

The bond angle in a bent molecule like SnCl₂ deviates from the typical 180 degrees and is approximately 120 degrees. This bent shape confirms that SnCl₂ is non-linear.

Hence, the correct answer is:

Option A: TRUE