Which statement about gels and pastes on porous surfaces is true?

Which statement about gels and pastes on porous surfaces is true?

• A. They may degrade surface finishes of porous materials.
• B. They can stain porous surfaces.
• C. They harden on contact with moisture.
• D. They improve resistance to staining.

Answer: (B)

Porous surfaces readily absorb liquids and dissolved colorants from gels or pastes, so residues can become trapped in the pores or migrate to the surface as the product dries. This makes staining a common and expected outcome when these formulations are used on porous materials. The pigments or dyes in the gel or paste can leave noticeable discoloration that is difficult to remove, which is why that statement is true. In contrast, degradation of surface finishes isn’t guaranteed for all products, hardening on moisture isn’t universal across formulations, and these products don’t inherently improve resistance to staining; in many cases they can contribute to staining instead.

Porous surfaces readily absorb liquids and dissolved colorants from gels or pastes, so residues can become trapped in the pores or migrate to the surface as the product dries. This makes staining a common and expected outcome when these formulations are used on porous materials. The pigments or dyes in the gel or paste can leave noticeable discoloration that is difficult to remove, which is why that statement is true. In contrast, degradation of surface finishes isn’t guaranteed for all products, hardening on moisture isn’t universal across formulations, and these products don’t inherently improve resistance to staining; in many cases they can contribute to staining instead.