(1)①
;②d
(2)①;③b
(3)(b-a-4c)/2
(4)①CH 3OH;O 2;②O 2+4e -+4H +=2H 2O;③1.2
(5) Al-3e -=Al 3+、Al 3++3HCO 3 -=Al(OH) 3↓+3CO 2↑