Answer: Na2C2O4 probably sodium oxalate
Explanation: assume you have 100 g substance.
Mass of Na is m(Na) = 34.31 g, m(C) = 17.93 g and m(O) = 47.76 g.
Calculate moles n(Na) = 34.31 g/22.99 g/mol= 1.49 mol.
For C n(C) = 1.49 mol and n(O) = 2.985. You divide all by 1.49 you
Get n(Na) : n(C) : n(O) = 1:1:2 M(NaCO2) = 67 g/mol.
Divide 134:67 = 2. You get formula Na2C2O4