The reaction is:
(CH3CO)2O + H2O = 2 CH3COOH
The synthesis reaction is.... Cu + Cl2 --> CuCl2
2H2 + O2 --> 2H2O Simple water synthesis.
2Na + Br2 = 2NaBr
2Mg + O2 → 2MgO
Co + 2h2 -> ch3oh
Na2O + CO2 -> Na2CO3 Balanced as is and I would call this a synthesis reaction.
H2,g + I2,s --> 2HIg
CaO + H2O =Ca(OH)2
That's a synthesis, or combination reaction. These types of reactions generally have 2 reactants and 1 product.
This is a balanced equation and this is a Synthesis type of reaction
Read details at this useful link.
LiOH2 P2O5H2O