The largest number of molecules is in

Each mole contains Avagadro's number of molecules.No of moles=Mass in gGram Molecular weight36 g of water is 2 moles; 28 g of CO is 1 mole; 46 g of Ethanol is 1 mole and 54 g of Nitrogen pentoxide is 0.5 mole∴   36 g of water has highest number of molecules.