To improve suspension stability by adjusting the dispersion medium, which action is recommended?

To improve suspension stability by adjusting the dispersion medium, which action is recommended?

• A. Decrease viscosity
• B. Increase temperature
• C. Increase viscosity
• D. Decrease temperature

Answer: (C)

Increasing the viscosity of the dispersion medium is the best move because it slows how fast suspended particles settle. Sedimentation velocity is inversely related to viscosity (as viscosity goes up, settling slows), so adding thickening agents to the medium reduces settling and helps keep the suspension uniform over time. Decreasing viscosity or increasing temperature would speed up settling, and while decreasing temperature can raise viscosity, that’s a storage condition, not a routine formulation adjustment to the dispersion medium.

Increasing the viscosity of the dispersion medium is the best move because it slows how fast suspended particles settle. Sedimentation velocity is inversely related to viscosity (as viscosity goes up, settling slows), so adding thickening agents to the medium reduces settling and helps keep the suspension uniform over time. Decreasing viscosity or increasing temperature would speed up settling, and while decreasing temperature can raise viscosity, that’s a storage condition, not a routine formulation adjustment to the dispersion medium.