NH4Al(SO4)2和NaOH
2个回答

NaOH少量:(先和Al3+反应,因为如果先和NH4+反应得到NH3,NH3还会与Al3+反应)

2 NH4Al(SO4)2 + 6 NaOH = (NH4)2SO4 + 2 Al(OH)3↓ + 3 Na2SO4

Al3+ + 3 OH- = Al(OH)3↓

NaOH适量:

NH4Al(SO4)2 + 4 NaOH = NH3 ↑+ Al(OH)3↓ + 2 Na2SO4 + H2O

NH4+ + Al3+ + 4 OH- = NH3 ↑+ Al(OH)3↓ +H2O

NaOH过量:

NH4Al(SO4)2 + 5 NaOH = NH3 ↑+ NaAlO2 + 2 Na2SO4 + 3 H2O

NH4+ + Al3+ + 5 OH- = NH3 ↑+ AlO2- + 3 H2O

可以发现,NH4Al(SO4)2 与NaOH的化学计量数之比依次是1:3 1:4 1:5