How many grams of HCL will react with 20 grams of Na?

Given:
m (Na) = 20 g

To find:
m (HCl) -?

Solution:
1) Write the reaction equation:
2HCl + 2Na => 2NaCl + H2 ↑;
2) Calculate the molar masses of Na and HCl:
M (Na) = Ar (Na) = 23 g / mol;
M (HCl) = Mr (HCl) = Ar (H) * N (H) + Ar (Cl) * N (Cl) = 1 * 1 + 35.5 * 1 = 36.5 g / mol;
3) Calculate the amount of substance Na:
n (Na) = m (Na) / M (Na) = 20/23 = 0.87 mol;
4) Determine the amount of HCl substance:
n (HCl) = n (Na) = 0.87 mol;
5) Calculate the mass of HCl:
m (HCl) = n (HCl) * M (HCl) = 0.87 * 36.5 = 31.8 g.

Answer: The mass of HCl is 31.8 g.