Final answer:
To calculate the volume of hydrogen gas produced, first calculate the moles of H3PO4, then use the stoichiometry of the reaction to find the moles of H2, and finally calculate the volume of H2. Assuming STP conditions, the volume of H2 would be 3494.4 mL, which does not match any of the provided options, indicating a possible error in the options or the calculation conditions.
Step-by-step explanation:
To calculate the volume of hydrogen gas (H2) produced from a reaction involving 118.5 mL of a 0.8775-M solution of H3PO4, we use the provided chemical equation: 2Cr + 2H3PO4 → 3H2 + 2CrPO4.
First, we determine the number of moles of H3PO4 using the molarity and volume:
- Number of moles of H3PO4 = Molarity × Volume (in liters) = 0.8775 mol/L × 0.1185 L = 0.1040 mols
Next, using the stoichiometry of the balanced equation, we find the moles of H2 produced:
- Moles of H2 = (3 moles H2 / 2 moles H3PO4) × 0.1040 moles H3PO4 = 0.1560 moles H2
Assuming the reaction takes place at Standard Temperature and Pressure (STP) where 1 mole of a gas occupies 22.4 liters, we calculate the volume of H2:
- Volume of H2 = 0.1560 moles × 22.4 L/mol = 3.4944 L = 3494.4 mL
However, since none of the offered answer options match our calculation, it is possible that there is an error in the provided options or in the calculation conditions. It is important to check the conditions under which the reaction takes place and to verify the answer options.