Compound $A$ gives $D$-Galactose and $D$-Glucose on hydrolysis. The compound $A$ is:

Starch can be used as an indicator for the detection of traces of

Identify the number of oxygen atoms present in saccharic acid.

The correct corresponding order of names of four aldoses with configurations given below,respectively,is:
$(1)$ $CHO-CH(OH)-CH(OH)-CH_2OH$ (both $-OH$ on right)
$(2)$ $CHO-CH(OH)-CH(OH)-CH_2OH$ ($-OH$ on left at $C-2$,right at $C-3$)
$(3)$ $CHO-CH(OH)-CH(OH)-CH_2OH$ (both $-OH$ on left)
$(4)$ $CHO-CH(OH)-CH(OH)-CH_2OH$ ($-OH$ on right at $C-2$,left at $C-3$)

Which of the following is a reducing sugar?

Match List-$I$ with List-$II$:

List-$I$	List-$II$
$A$. Glucose/$NaHCO_3$/$\Delta$	$I$. Gluconic acid
$B$. Glucose/$HNO_3$	$II$. No reaction
$C$. Glucose/$HI$/$\Delta$	$III$. $n$-hexane
$D$. Glucose/Bromine water	$IV$. Saccharic acid

Choose the correct answer from the options given below: