Verified answer

 25 г                                                                       Х л

  Zn             +          2HCl       =      ZnCl2       +      H2

n = 1 моль                                                           n = 1 моль

Mr = 65 г/моль                                                    Vm=22,4 л/моль

m = 65 г                                                               V = 22,4 л

25 г Zn      -      Х л Н2

65 г Zn      -     22,4 л Н2

V(H2) = 25 * 22,4 / 65 = 8,6 л