oxidising & reducing agents

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Oxidising agents or oxidants : are substances which

• Show gain of electrons
• Oxidise other substances
• are reduced themselves
• Show a decrease in oxidation no.

Reducing Agents or Reductants : are substances which

• Show loss of electrons
• reduce other substances
• are oxidised themselves
• show an increase in oxidation no.

Redox reaction is a process in which reducing agent is oxidised & liberate electrons, which are then taken up by an oxidising agent to get itself reduced. In redox rxns oxidation and reduction occur simultaneously.

Ex.

• Identify the oxidizing agent and the reducing agent in the following redox reaction:
MnO2(s)+4H+(aq)+2Cl(aq)Mn2+(aq)+2H2O(l)+Cl2(g)

• Cl

is the reducing agent because it is oxidized and loses one electron (starting with an oxidation state of -1 in the Cl ions and increasing to 0 in Cl2). Remember that gaining electrons means it is “reduced”.  MnO2 is the oxidizing agent because it is reduced by gaining two electrons (starting with Mn in an oxidation state of +4 in MnO2 and decreasing to +2 in free Mn2+

• ions). Keep in mind that losing electrons means it is “oxidized”.