Question

formaldehyde has a wide range of uses, many of them in manufacturing. its chemical formula is ch₂o. the model below represents formaldehyde. based on the model, which statement best describes formaldehyde molecules?
a. formaldehyde molecules do not form a repeating pattern and cannot freely move past each other.

b. formaldehyde molecules do not form an extended structure and can freely move past each other.

c. formaldehyde molecules form a repeating pattern and can freely move past each other.

d. formaldehyde molecules form an extended structure and cannot freely move past each other.

Explanation:

Formaldehyde ($\ce{CH2O}$) is a molecular compound. Molecular compounds (like those in gases or liquids, or solids with molecular structures) have molecules that are discrete (not forming an extended, repeating lattice structure like ionic or covalent network solids). In the model, the molecules are separate and can move past each other (as in a gas or liquid state, or even in solid molecular crystals, molecules can have some mobility or are not locked in a rigid extended structure).

• Option A: Says they can't move past each other, which is wrong (molecular compounds' molecules can move, e.g., in liquid or gas).
• Option B: Molecules don't form an extended structure (since they are discrete $\ce{CH2O}$ molecules, not a lattice of repeating units like in NaCl or diamond) and can freely move past each other (consistent with molecular behavior in fluid states or even in some solid molecular arrangements where molecules can rotate/vibrate).
• Option C: Says they form a repeating pattern, but molecular compounds don't have a repeating lattice of molecules (the pattern is within the molecule, not the arrangement of molecules in a lattice like a crystal with extended structure).
• Option D: Says they form an extended structure, which is incorrect for molecular compounds (extended structures are for ionic, covalent network, or metallic solids, not molecular solids with discrete molecules).

So the correct reasoning leads to Option B.

Answer:

B. Formaldehyde molecules do not form an extended structure and can freely move past each other.