In a dilution of 2 mL soln to 8 mL solvent, which pair of ratios correctly represents solute to total volume and solute to solvent?

• A. 2:8, 2:10
• B. 10:2, 8:2
• C. 2:10, 2:8
• D. 8:2, 10:2

Answer: (C)

When you dilute, you compare the amount of solute to both the total volume and to the solvent used. Here, 2 mL of solute is mixed with 8 mL of solvent, so the total volume becomes 2 + 8 = 10 mL.

Solute to total volume is 2 mL solute : 10 mL total, i.e., 2:10 (which simplifies to 1:5 if you prefer).

Solute to solvent is 2 mL solute : 8 mL solvent, i.e., 2:8 (which simplifies to 1:4).

So the correct pair is 2:10 for solute to total and 2:8 for solute to solvent. The other options either mix up the denominators or swap the ratios, not representing the two defined relationships in the same order.