Final answer:
Without a balanced chemical equation and the conditions under which the reaction takes place, it is not possible to accurately answer how many liters of hydrogen gas are formed from the reaction of 25.7 g of carbon.
Step-by-step explanation:
The student asked how many liters of hydrogen gas are formed from the complete reaction of 25.7 g of carbon (C). However, to answer this, we need a balanced chemical reaction that includes carbon reacting to form hydrogen gas, and the conditions like temperature and pressure or the fact that the volumes of gases react in the ratio of their coefficients at the same conditions. Since none is provided in the question and with the information given, we cannot determine the amount of hydrogen gas formed directly. Typically, in such problems, the reaction would likely be that of a hydrocarbon with oxygen, but without a specific reaction, we cannot proceed.
If we had the balanced equation, we would use the molar mass of carbon to find the moles of carbon reacted, use the stoichiometry of the reaction to find the moles of hydrogen gas formed, and then use the ideal gas law or Avogadro's principle at standard conditions to find the volume of hydrogen gas produced.