Balance tis equation:

HCl + Na2CO3 --> NaCl + H2O + CO2

C2H5OH + KMnO4 --> CH3COOH + MnCl2 (Acidic condition, use HCl)

P2O5 + H2O --> H3PO4

H2O2 + H2C2O4 --> H2 + H2O + CO2