Hydrogen H2 reacts with oxygen O2 to produce water H2O according to the following proportion:
2 moles of H2 react with 1 mole of O2 to produce 2 moles of H2O (balanced equation)
0.46 g of H2 is 0.228 moles of H2 which are going to react with 0.114 moles of O2 (half the moles of H2 according to the above proportion) to produce 0.228 moles of H2O (again, according to above proportion). You can check there is more than enough O2 to consume all of the H2 and there will be some O2 leftover.
0.228 moles of water in grams is 0.228 mol * (18.02 g/mol) = you do the math (the result in grams)
Note: if you don't understand the concept of molar mass and proportions it will be hard for you to solve chemical reactions.