What type of resin dissolves in water?

• A. Neither natural nor synthetic
• B. Natural
• C. Synthetic
• D. Both natural and synthetic

Answer: (A)

Resins are typically water-insoluble because they are large, long-chain polymers that are either nonpolar or highly crosslinked. Water is a polar solvent, and dissolving such polymers would require strong interactions between water and the polymer chains, which these resins lack. Natural resins (like rosin-based substances) are mainly nonpolar hydrocarbons with some functional groups, so they don’t dissolve in water. Synthetic resins used in embedding and coatings (epoxy, polyester, acrylics, etc.) are often highly crosslinked or have high molecular weights, making them resistant to dissolution in water as well. In most practical contexts, including histology, water does not dissolve either natural or synthetic resins, so the correct idea is that neither type dissolves in water.