Bạn tham khảo:
$C_2H_2 +2H_2 \to C_2H_6$
$HCHO +H_2 \to CH_3OH$
$C_2H_2+2AgNO_3 +2NH_3 \to Ag_2C_2 +2NH_4NO_3$
$HCHO+5AgNO_3+6NH_3 +2H_2O \to 4Ag+4NH_4NO_3+(NH_4)_2CO_3$
$n_{C_2H_2}=a(mol)$
$n_{HCHO}=b(mol)$
$m_{hh}=26a+30b=11,2(1)$
$n_{H_2}=2a+b=0,6(2)$
$(1)(2)$
$a=b=0,2(mol)$
$m=0,2.240+0,8.108=134,4(g)$
$\to A$