the diagram below is a model of two solutions. each green ball represents one particle of solute. which…

Explanation:

Step1: Calculate concentration of Solution A

Concentration formula: (C=\frac{n}{V}) (where (n) is the number of solute particles, (V) is the volume of solvent). For Solution A, (n = 10), (V=40\space mL). So (C_A=\frac{10}{40}=\frac{1}{4}\space particles/mL)

Step2: Calculate concentration of Solution B

For Solution B, (n = 2), (V = 20\space mL). So (C_B=\frac{2}{20}=\frac{1}{10}\space particles/mL)

Step3: Compare concentrations

Since (\frac{1}{4}>\frac{1}{10}) (because (\frac{1}{4}= 0.25) and (\frac{1}{10}=0.1))

Answer:

Solution A