The standard reduction potentials at 298K, for the following half cells are given:
`Zn^(2+)(aq)+2e^(-)hArrZn(s):E^(@)=-0.762V`
`Cr^(3+)(aq)+3e^(-)hArrCr(s):E^(@)=-0.740V`
`2H^(+)(aq)+2e^(-)hArrH_(2)(g), E^(@)=0.000V`
`Fe^(3+)(aq)+e^(-)hArrFe^(2+)(aq),E^(@)=0.770V`
Which is the stronget reducing agent?

Options

A. `Zn(s)`
B. `Cr(s)`
C. `H_(2)(s)`
D. `Fe^(2+)(aq)`

Answer

A

Explanation

The metals having regative value of standart reduction potential are placed above hydrogen in electrochemical series. The metals placed above hydrogen has a great power. The metals having great oxidising pwer are strongest redcing agent. Zn has higher negative value of standard reduction potential . Therefore, it is the strongest reducing agent.