$\mathrm{Glucose}\stackrel{\mathrm{Conc}.{\mathrm{HNO}}_3}{\to }\mathrm{X};\mathrm{Glucose}\stackrel{{\left[\mathrm{Ag}{\left({\mathrm{NH}}_3\right)}_2\right]}^{+}}{\to }\mathrm{Y};$X and Y respectively ar

$\mathrm{OHC} -{\left(\mathrm{CHOH}\right)}_4-{\mathrm{CH}}_2\mathrm{OH} \stackrel{\mathrm{Tollen} \mathrm{reagent}}{\to }\mathrm{HOOC}-{\left(\mathrm{CHOH}\right)}_4-{\mathrm{CH}}_2\mathrm{OH}$

Conc. nitric acid oxidizes both aldehyde group and primary alcohol  group to carboxylic acid.

Tollens reagent is a mild oxidant, it oxidizes only aldehyde group to carboxylic acid