Final answer:
None of the provided answer choices correctly indicate the amount of zinc hydroxide formed from 30.7 grams of water with excess zinc oxide. The mass of zinc hydroxide produced can only be calculated with the balanced chemical equation and molar masses, which were not provided in the question.
Step-by-step explanation:
According to the reaction of water with excess zinc oxide to form zinc hydroxide, the answer to how many grams of zinc hydroxide will be formed when 30.7 grams of water completely reacts is not provided by any of the choices (A, B, C, or D). To calculate this, we would need the balanced chemical equation for the reaction between zinc oxide and water, which typically would be ZnO + H2O → Zn(OH)2. From there, we could use stoichiometry to convert the grams of water into moles, and then determine the moles and, eventually, the mass of the zinc hydroxide produced.
However, based on the options provided and the information given, none of the options (A, B, C, or D) are correct. The question lacks the necessary information such as the balanced chemical equation and the stoichiometric coefficients. Therefore, the accurate response would be that we need the balanced equation and molar masses to calculate the mass of zinc hydroxide produced.