First question what is C8H8O3 and C8H10O3.
Calciumhydride is a reducer and add hydrogen to the molecule.I think in the equation water is missing, if we reduce an aldehyde. Do we?
Normal R-CHO + H- => RCH2O-
This reacts with H2O
RCH2O- + H2O => RCH2OH + OH-.