50g CaCO_​3 will react with how many grams of 20% HCl by weight

1. The reaction in the numerical involved is as follows:

     CaCO₃ (aq) + 2 HCl (aq) $\to$ CaCl_​2 (aq)+ H₂O(l) + CO₂(g)

2. 1 mole of Calcium Carbonate reacts with 2 mole of HCl.

 or 0.5 mole of Calcium Carbonate reacts with 1 mole of HCl.

Number of moles of Calcium Carbonate = $\frac{50}{100} = 0.5 mole.$

3. The molar mass of HCl is 36.5 g/mol.

  20 g of HCl is present in 100 g of solution.
Thus, the mass of the 20% solution of 36.5 g of HCl is
.$m(HCl solution) = \frac{m\left(HCl\right)}{w\left(HCl\right)}=\frac{36.5}{0.2} = 182.5 g.$