Magnesium reacts with hydrochloric acid in a sealed container, as shown. The initial pressure inside the container is 1.20 atm and its volume is 100 mL. What is the pressure inside the container after 243 mg of magnesium has reacted? (Note: Assume the reaction is isothermal and the gas behaves ideally.) Mg(s) + 2HCl(aq) → MgCl2(s) + H2(g) A.1.4 atmB.2.4 atmC.3.6 at

To solve this problem, we need to use the ideal gas law and stoichiometry.

Step 1: Convert the mass of magnesium to moles. The molar mass of magnesium (Mg) is approximately 24.31 g/mol.

243 mg = 0.243 g

So, moles of Mg = 0.243 g / 24.31 g/mol = 0.01 mol

Step 2: According to the balanced chemical equation, 1 mole of Mg produces 1 mole of H2 gas. So, 0.01 mol of Mg will produce 0.01 mol of H2 gas.

Step 3: Use the ideal gas law (PV=nRT) to find the pressure of the produced H2 gas. We know that R (the ideal gas constant) is 0.0821 L.atm/(mol.K), T (temperature) is constant (isothermal conditions), and V (volume) is 100 mL = 0.1 L.

So, P = nRT/V = (0.01 mol * 0.0821 L.atm/(mol.K) * T) / 0.1 L

We don't know the exact temperature, but since the conditions are isothermal, the temperature before and after the reaction is the same. Therefore, the pressure of the produced H2 gas is directly proportional to the number of moles, which is 0.01 atm.

Step 4: The initial pressure inside the container was 1.20 atm. The pressure of the produced H2 gas is added to this initial pressure because the reaction is happening in a sealed container.

So, the final pressure inside the container = initial pressure + pressure of H2 gas = 1.20 atm + 0.01 atm = 1.21 atm

However, none of the given options (A.1.4 atm, B.2.4 atm, C.3.6 atm) match this result. There might be a mistake in the question or the given options.