Which is the correct order of increasing oxidising ability?

Options

A. `Pb^(2+) lt Ni^(2+) lt Cr^(3+)+ lt Al^(3+)`
B. `AI^(3+) lt Cr^(3+) lt Ni^(2+) lt Pb^(2+)`
C. `Cr^(3+) lt AI^(3+) lt Ni^(2+) lt Pb^(2+)`
D. `Ni^(2+) lt Pb^(2+) lt AI^(3+) lt Cr^(3+)`

Answer

B

Explanation

`E_(Ni^(2+)//Ni)^@=-0.25` V
`E_(Cr^(3+)//Cr)^@=-0.74` V
`E_(AI^(3+)//AI)^@=1.66` V
`E_(Pb^(2+)//Pd)^@=-0.13` V

Higher the value of reduction potential (high positive), stronger will be oxidising capacity
Thus, oxidising ability is in the order :
`AI^(3+) < Cr^(3+) < Ni^(2+) < Pb^(2+)`