The standard reduction potentials at 298 K for the following half-cell reactions are given below Zn 2+(a q)+2 e- leftharpoons Zn (s)-0.762 Cr 3+(a q)+3 e- leftharpoons Cr (s)-0.74 2 H +(a q)+2 e- leftharpoons H 2(g) 0.00 Fe 3+(a q)+e- leftharpoons Fe 2+(a q)+0.77 Which one of the following is the strongest reducing agent?

Question

The standard reduction potentials at 298 K for the following half-cell reactions are given below Zn 2+(a q)+2 e- leftharpoons Zn (s)-0.762 Cr 3+(a q)+3 e- leftharpoons Cr (s)-0.74 2 H +(a q)+2 e- leftharpoons H 2(g) 0.00 Fe 3+(a q)+e- leftharpoons Fe 2+(a q)+0.77 Which one of the following is the strongest reducing agent? (A)  Zn(s)  (B)  Cr(s)  (C) H2(g) (D)  Fe2+(aq)

Tardigrade Admin · Accepted Answer

The metals having higher negative value of standard reduction potential are placed above hydrogen in electrochemical series. The metals placed above hydrogen has a great tendency to donate electrons or to undergo oxidation. The metals having great power to undergo oxidation are strongest reducing agent. Zn has highest negative value of standard reduction potential. Therefore, it is the strongest reducing agent.

$Z n (s)$

$C r (s)$

$H_{2} (g)$

$F e^{2 +} (a q)$

Q. The standard reduction potentials at 298K for the following half-cell reactions are given below Zn2+(aq)+2e−⇌Zn(s)−0.762 Cr3+(aq)+3e−⇌Cr(s)−0.74 2H+(aq)+2e−⇌H2​(g)0.00 Fe3+(aq)+e−⇌Fe2+(aq)+0.77 Which one of the following is the strongest reducing agent?

Zn(s)

Cr(s)

H2​(g)

Fe2+(aq)

$Z n (s)$

$C r (s)$

$H_{2} (g)$

$F e^{2 +} (a q)$