Question

Which equation is a reduction half-reaction that is written correctly?

Zn2+(aq) + e– mc004-1.jpg Zn(s)
Be2+(aq) + 2e– mc004-2.jpg Be(s)
2Cl–(aq) mc004-3.jpg Cl2(g) + 2e–
Au(s) mc004-4.jpg Au3+(aq) + 3e–

Answer 1

Answer: The correct answer is B.

Answer 2

Reduction reaction means addition of electrons. Hence options C and D are rejected.

Coming to the first reduction-half reaction,
Zn+2 gains 1 electron and forms Zn. It should be Zn+, hence 1st reduction half reaction is also rejected.

So the correct reduction-half reaction is:

Be+2(aq) + 2e ------------------> Be(s)

Hope this helps!