Mg can react with HCl to produce the white solid MgCl₂ and H₂ gas.A student mixes 1.99 g of Mg with 5.98 g of HCl.If the mass of the white solid is 7.79 g,then what is the mass of H₂ produced?

Question

Quizplus · Accepted Answer

We need to first find the limiting reactant to determine how much H₂ gas is produced. Mg + 2HCl -> MgCl2 + H2 Using stoichiometry, we can find that 1 mole of Mg reacts with 2 moles of HCl producing 1 mole of H2 gas. The moles of Mg given: 1.99g / 24.31 g/mol = 0.0819 mol The moles of HCl given: 5.98g / 36.46 g/mol = 0.164 mol Since there are fewer moles of Mg, it is the limiting reactant. Therefore, all of the Mg will react, and the amount of H₂ gas produced will be determined by the amount of HCl left over after the reaction. Mg + 2HCl -> MgCl2 + H2 0.0819 mol Mg * 2 mol HCl / 1 mol Mg = 0.164 mol HCl required 0.164 mol HCl - 0.164 mol HCl given = 0 moles of HCl left over Therefore, all of the HCl is used up in the reaction, and there is no H₂ gas produced. The only product is the white solid MgCl2, which has a mass of 7.79 g. The mass of H₂ produced is 0.0 g. Therefore, the best choice is B with the explanation provided.

Mg Can React with HCl to Produce the White Solid