If the mobile phase becomes more polar, polar compounds typically move ?

If the mobile phase becomes more polar, polar compounds typically move ?

• A. Move faster
• B. Move slower
• C. No change
• D. Move unpredictably

Answer: (A)

When the solvent that carries the sample through the column becomes more polar, polar compounds are solubilized more strongly by the mobile phase and interact less with the stationary phase. In the common reversed‑phase setup, the stationary phase is nonpolar and the mobile phase is relatively polar. Making the mobile phase more polar increases the solvation of polar solutes in the solvent, so they spend less time sticking to the nonpolar surface and travel through the column faster. The result is earlier elution, or moving faster. So the correct interpretation is that polar compounds tend to move faster as the mobile phase polarity increases. The other options would require different conditions or do not reflect this solvating effect.

When the solvent that carries the sample through the column becomes more polar, polar compounds are solubilized more strongly by the mobile phase and interact less with the stationary phase. In the common reversed‑phase setup, the stationary phase is nonpolar and the mobile phase is relatively polar. Making the mobile phase more polar increases the solvation of polar solutes in the solvent, so they spend less time sticking to the nonpolar surface and travel through the column faster. The result is earlier elution, or moving faster.

So the correct interpretation is that polar compounds tend to move faster as the mobile phase polarity increases. The other options would require different conditions or do not reflect this solvating effect.