Paint materials — commonly used drying oil In building and protective coatings, which of the following is the most commonly used drying oil for preparing traditional oil paints (serving as the vehicle/binder that hardens by oxidation)?

Introduction / Context:
Oil paints used in civil engineering and architectural works rely on a “vehicle” (binder) that dries to a tough film. Drying oils polymerise upon exposure to oxygen, converting the liquid paint into a solid, protective coating. Identifying the correct drying oil is foundational to paint technology.

Given Data / Assumptions:

• The question asks for the commonly used drying oil in traditional oil paints.
• “Drying oil” means an oil that forms a hard film by oxidative polymerisation.
• Use in construction contexts such as woodwork, metal railings, doors, and trim.

Concept / Approach:
Linseed oil, obtained from flax seeds, is rich in polyunsaturated fatty acids (notably linolenic acid). These unsaturated bonds react with atmospheric oxygen, creating crosslinked polymers. The result is a continuous, durable film that binds pigments and adheres to the substrate.

Step-by-Step Solution:

Verification / Alternative check:
Paint specifications and standards consistently list refined or boiled linseed oil as the classic vehicle. Alternatives (tung oil) exist but linseed oil remains the most widespread in construction practice.

Why Other Options Are Wrong:

• Olive oil: non-drying or very slow; unsuitable as a primary paint vehicle.
• Kerosine oil: a solvent/thinner, not a binder; it evaporates and does not form a film.
• Accetate of lead: a siccative/drier historically used in tiny amounts to accelerate drying; not itself a drying oil.

Common Pitfalls:
Confusing vehicles (binders) with thinners/solvents. A solvent adjusts viscosity and evaporates; the drying oil remains to form the film.

Final Answer: