What mass of 20% hydrochloric acid is required to completely dissolve a marble statuette (no impurities) weighing 50 g?

Let’s write the reaction equation:

CaCO3 + 2HCl = CaCl2 + CO2 ↑ + H2O

Let’s find the amount of calcium carbonate substance (by condition, the figurine is completely made of it):

v (CaCO3) = m (CaCO3) / M (CaCO3) = 50/100 = 0.5 (mol).

According to the reaction equation, 1 mol of CaCO3 reacts with 2 mol of HCl, therefore:

v (HCl) = v (CaCO3) * 2 = 0.5 * 2 = 1 (mol).

Let’s find the mass of hydrogen chloride:

m (HCl) = v (HCl) * M (HCl) = 1 * 36.5 = 36.5 (g).

Find the mass of the hydrochloric acid solution:

mr.-ra (HCl) = m (HCl) * 100 / w (HCl) = 36.5 * 100/20 = 182.5 (g).

Answer: 182.5 g.