Question

In the reaction: pb + 2ag+ → pb2+ + 2ag, the oxidizing agent is

Answer 1

With reference to present question, following things may be noted
1) Oxidation is process of lose of electron. Atom//ion undergoing oxidation is refereed as reducing agent
2) Reduction is process of gain of electron. Atom/ion undergoing reduction is refereed as oxidizing agent.

in present system, Ag+ gain an electron to reduced to Ag. Therefore, Ag+ is an oxidizing agent. 

Answer 2

Answer: The oxidizing agent for the given reaction is Silver.

Explanation:

Oxidizing agent is defined as the agent which helps the other substance to get oxidized and itself gets reduced. It undergoes reduction reaction in which a substance gains electrons. The oxidation state of this substance gets reduced and the substance gets reduced.

Reducing agent is defined as the agent which helps the other substance to get reduced and itself gets oxidized. It undergoes oxidation reaction in which a substance looses its electrons. The oxidation state of this substance gets increased and the substance gets oxidized.

For the given chemical reaction:

$Pb+2Ag^+\rightarrow Pb^{2+}+2Ag$

The half reactions for the given above chemical reaction is:

Oxidation half reaction:  $Pb\rightarrow Pb^{2+}+2e^-$

Reduction half reaction: $2Ag^++2e^-\rightarrow 2Ag$

As, lead is loosing electrons. So, it is getting oxidized and is considered as a reducing agent and silver is gaining electrons. So, it is getting reduced and is considered as an oxidizing agent.

Thus, the correct answer is silver.