How many optical isomers does glucose have?

Predict the product of the following reaction:
$Glucose \xrightarrow{Br_2/H_2O} \text{Product}$

Stachyose is a

Which of the following statements is incorrect regarding $Ribose$ sugar?

Monosaccharides contain a carbonyl group and are hence classified as aldose or ketose. The number of carbon atoms present in the monosaccharide molecule is also considered for classification. In which class of monosaccharide will you place fructose?

With which reagent does glucose react to form a crystalline osazone derivative?