It is a pale yellow powder, but on exposure to moisture and CO2 it turns to white. The product is
NaOH
Na2O2
Na2O
2Na2O2 + 2H2O → 4NaOH + O2
2Na2O2 + 2CO2 → 2Na2CO3 + O2
NaOH and Na2CO3 are white in colour.