Why is Benedict's solution used to test for maltose?

Answer 1

Benedict's reagent (often called Benedict's qualitative solution or Benedict's solution) is a chemical reagent and complex mixture of sodium carbonate, sodium citrate and copper(II) sulfate pentahydrate" (Wikipedia)

Broadly speaking, Benedict reagent can be used to test a reduction-oxidation reaction due to the presence of the copper (II) ingredient. Regards to the question, Benedict reagent is suited to test reducing sugars. If the maltose is a reducing sugar, it will reduce the Benedict's copper (II) to copper (I), resulting in a color change in the solution.