Zinc is more active than cobalt and iron but less active than aluminum. cobalt is more active than nickel but less active than iron. which of the following correctly lists the elements in order of increasing activity?
a) zn < al < co < ni < feb) co < ni < fe < zn < alc) fe < ni < co < al < znd) ni < co < fe < zn < ale) ni < fe < co < zn < al

d) Ni < Co < Fe < Zn < Al

Explanation:

electronegativity of Aluminium  1.6

electronegativity of Zinc  1.7

electronegativity of iron  1. 83

electronegativity of Cobalt  1.88

electronegativity of Nickel  1.91

As the electronegativity of aluminium is lower as compared to other, so it will have high tendency to easily lose electron and that is why Aluminium is more reactive than the other mentioned

it is b that is the answer.