Define carbohydrates. What are reducing and non reducing sugars ?

Explanation

Carbohydrates : Carbohydrates are optically active polyhydroxy aldehydes or polyhydroxy ketones, or the compounds which on hydrolysis produce polyhydroxy aldehydes or polyhydroxy ketones.
Exampes : Glucose, sucrose, fructose.
Reducing sugars : Carbohydrates which reduces Fehling's solution to red ppt. of `Cu_(2)O` or Tollen's reagent to shining metallic silver are called reducing sugars. All monosaccharides and oligosaccharides except sucrose are reducing sugars.
Non-reducing sugars : Carbohydrates which do not reduce Fehling's solution and Tollen's reagent are called non-reducing sugars. e.g., sucrose.