Which of the following substances will give the Molisch test?

$\beta-D-(+)-$Glucopyranose is represented by which of the following structures?

In aqueous solution,glucose remains as:

$\alpha - D - (+)$ glucose and $\beta - D - (+)$ glucose are

Identify the carbon atoms of glucose and of fructose forming the glycosidic bond in sucrose.

$L$-isomer of tetrose $X$ $(C_4H_8O_4)$ gives positive Schiff's test and has two chiral carbons. On acetylation,$X$ yields triacetate. $X$ also undergoes the following reactions:
$X$ $\xrightarrow{HNO_3} A$ $\xrightarrow{NaBH_4} \underset{\text{Chiral compound}}{B}$
$X$ is $.......$.