n(Zn)=
0.195g
65g/mol =0.003mol,
n(MO 2 +)=0.02L×0.100mol•L -1=0.002mol,
设反应后M的化合价为+x价,
则(5-x)×0.002mol=0.003mol×(2-0),
x=2,
故选B.
n(Zn)=
0.195g
65g/mol =0.003mol,
n(MO 2 +)=0.02L×0.100mol•L -1=0.002mol,
设反应后M的化合价为+x价,
则(5-x)×0.002mol=0.003mol×(2-0),
x=2,
故选B.