QJEEM19Ch2cb4: JEE Main 2019 Chemistry - Class 12 JEEM19Ch2cb4 Solution: Maltose on treatment with dilute HCI gives :

Maltose on treatment with dil. HCl gives D-glucose. Hydrolysis of maltose yields two moles of $\alpha$ - D-glucose. Thus, it is composed of two $\alpha$ -D-glucose units in which C-1 of one glucose unit (I) is linked to C-4 of another glucose unit (II). The free aldehyde group can be produced at C-1 of second glucose in solution and it shows reducing properties.
So, it is a reducing sugar.