0,2 моль                                                            Х л

   Сa           +         2HCl      ->    CaCl2      +       H2

n = 1 моль                                                        n = 1 моль

                                                                         Vm=22,4 л/моль

                                                                         V = 22,4 л

0,2 моль Са     -      Х л Н2

1 моль Са        -     22,4 л Н2

V(H2) = 0,2 * 22,4 / 1 = 4,48 л