How many liters of oxygen are required to produce 2 liters of water at stp?

Explanation:

Water molecule is H₂O, which means that there is one oxygen atom per each water molecule.

The balanced chemical equation that represents this is:

The stoichiometric coefficents 1 for O₂ (g) and 2 for H₂O (g) means that two molecules of oxygen are required to produce two molecules of water.

STP stands for standard temperature and pressure. Those conditions are 273.15 K (0 °C, 32 °F) and 100 KPa of absolute pressure.

That means that the reaction is carried out at constant temperature and pressure.

Then, since the  ideal gas law states that the at constant pressure and temperature the volume occupied by the gases is proportional to the number of particles (atoms or molecules), the molecular stoichiometric ratio of 1 molecule of O₂ (g) to 2 molecules for H₂O (g) is equivalent to the volumetric ratio 1 liter of O₂ to 2 liters of H₂O:

Hence, you conclude that 1 liter of oxygen is required to produce 2 liters of water, at STP.

c is the answer because when something is left after something evaporates that shows the chemical change.