CE Chem MC

Zn + 2HCl → ZnCl2 + H2
Step 1: Find the limiting agent / agent in excess
no. of mole of Zn = 21.8 / 65.4 = 1/3 mol
no. of mole of HCl = (250/1000)(2.0) = 0.5 mol
Hence HCl is limiting
[PS. 網上提供的版本有錯誤。HCl的concentration是2.0不是20]
Step 2: Find no. of mole of H2
No. of mole of H2 released = no of mole of HCl / 2 = 0.25 mol
Step 3: Find volume
Volume = 0.25 (24) = 6 dm3
Hence the answer is B