Redox reactions 2

In HNO3, N is in its max. oxidation state. It can only gain electrons and cannot lose. Whereas HNO2, N has Oxidation state +3, it can give or lose electrons, hence it is an oxidizing and reducing agent.

Redox reactions in which oxidation and reduction occurs in the same vessel are known as direct redox reactions.

Redox reactions in which oxidation and reduction takes place in different vessels are called indirect redox reactions. (Medium used -> Electrochemical cell)

Device used to convert chemical energy produced in an indirect redox reaction into electrical energy. also called Galvanic cell/ Voltaic cell/ Daniel cell.

The salt fridge is a U tube containing potassium chloride or ammonium nitrate solution usually solidified by boiling with agar agar gel and later cooling with a jelly like substance. FUNCTION: - 1. It allows the moment of ions without mixing the two solutions. 2. Helps maintain electrical neutrality of the solutions in the two half cells due to flow of Electrons.

Interphase between solid and aqueous solutions

Salt bridge

Tendency of an electrode to lose or gain electrons it is the potential associated with each electrode.

If the concentration of each solution taking part in the electrode reaction is unity. ( If any gas appears in electrode reaction, it is taken as one atmosphere).

Electromotive cell

0

• Negative E o Means that the Redox couple is a stronger reducing agent than H+/H2 couple. • Positive E o means that the redox couple is a weaker reducing agent than H+/ H2 couple.

• It is defined as having together the oxidized and reduced form of a substance taking part in an oxidation or reduction. • Represented by separating the oxidized form from the reduced form by a vertical line or slash.

• Left beaker contains zinc road dipped in zinc sulfate solution and the right speaker contains copper road dipped in copper sulfate solution • They are connected by a thin wire and zinc sulfate and copper sulfate solutions they are connected by salt bridge. • The electrons move from zinc road to copper road while the current flows from cathode to anode. • The Baker in which oxidation and reduction takes place oxidation half cell and reduction half cell respectively.