Question

室温下,在强酸性和强碱性溶液中都不能大量共存的离子组是?(请写下原理)

A

NH4+
H+
NO3-
HCO3-
B

K+
AL3+
SO42- NH3.H2O

C
NA+
K+
SO32-
CL2

D
NA+ CH3COO- CO32- OH-

Answer 1

题目有错.除非不考虑选项中混合溶液自身反应
C中应该是Cl-吧?

A.本身不共存,H+ + HCO3- = CO2↑ + H20 NH4+ + HCO3- + H2O= NH3H2O + H2CO3
B.本身不共存. Al3+ + 3NH3H2O = Al(OH)3↓ + 3NH4+
C.在强碱下可共存,强酸下不共存 SO32- + 2H+ = H2SO3
D.强酸下不共存,强碱下可共存 CH3COO- + H+ =CH3COOH OH- CO32- + 2H+ =H2CO3 OH- + H+ = H2O

无法选
如果不考虑选项中混合溶液自身反应
A.强酸强碱下均不共存.NH4+ + OH- = NH3H2O,H+ +OH- =H2O HCO3- + H+ =CO2↑ + H20 HCO3- + OH- = CO32- + H2O
B.强酸强碱下均不共存. Al3+ + 4OH- = Al02- + 2H20 NH3H2O + H+ = NH4+ +H20
C.在强碱下可共存,强酸下不共存 SO32- + 2H+ = H2SO3
D.强酸下不共存,强碱下可共存 CH3COO- + H+ =CH3COOH OH- CO32- + 2H+ =H2CO3 OH- + H+ = H2O

Answer 2

A