8 г                                                                     Х л

  2CH3-OH     +     2Na       =     2CH3ONa    +     H2

n = 2 моль                                                           n = 1 моль

Mr = 32 г/моль                                                    Vm = 22,4 л/моль

m = 64 г                                                               V = 22,4 л

8 г СН3-ОН    -    Х л Н2

64 г СН3-ОН   -    22,4 л Н2

V(H2) = 8 * 22,4 / 64 = 2,8 л