Molarity (M)=mwt×Vwt×1000
Using this formula, we can calculate the molarity of the oxalic acid solution as follows:
Mass of hydrated oxalic acid =3.1500g
Molar mass of hydrated oxalic acid(H2C2O4⋅2H2O)=126.064g/mol
Volume of the solution = 250.0mL
Molarity (M)=126×2503.15×1000=0.10
So both assertion land reason are correct.