presentation on hydrogen electrode (BMB 4th semester).pptx

It is a presentation slide on Biochemistry and Molecular Biology

1. Hydrogen electrode Submitted By: Shekhor Imtiaj Jumman Reg. No: 2020433033 Dept. of Biochemistry and Molecular Biology Submitted To: Moshiul Alam Mishu Assistant Professor Dept. of Biochemistry and Molecular Biology

2. contents What is Hydrogen Electrode? Components of Hydrogen Electrode Working principle of hydrogen electrode Advantages and disadvantages of hydrogen electrode Why hydrogen electrode is used as a reference electrode ? 20XX PRESENTATION TITLE 2

3. What is hydrogen electrode ? Hydrogen Electrode or The standard hydrogen electrode(SHE) is a redox electrode which forms the basis of the thermodynamic scale of oxidation-reduction potentials. It's absolute electrode potential is estimated to be 4.44±0.02 V at 25°C, but to form a basis for comparison with all other electrochemical reactions, hydrogens standard electrode potential (E°) is declared to be 0 volts at any temperature. 20XX PRESENTATION TITLE 3

4. Components of hydrogen electrode A standard hydrogen electrode has five components : Platinized platinum electrode. Acid solution that has a hydrogen ion (H + ) activity of 1 mol/dm 3 . Hydrogen gas bubbles (1 atm) Hydroseal to prevent interference from oxygen. Reservoir to attach the second-half element of the galvanic cell . There are a salt bridge or a narrow tube to prevent mixing may be used.

5. Working principle of hydrogen electrode In the molecular view, the Pt surface catalyzes the oxidation of hydrogen molecules to protons or the reduction of protons to hydrogen gas At the electrode hydrogen gas can either be oxidized to form hydrogen ions or hydrogen ions can be reduced to form hydrogen gas 20XX PRESENTATION TITLE 5

6. Working principle of hydrogen electrode Cell reaction Oxidation: ; E° H2/2H+ =0V Reduction: ; E° 2H+/H2 = 0V E° (SHE) = 0.0 V Cell representation: H + (1M)/ H 2 (g, 1 atm)/ Pt(s)   20XX PRESENTATION TITLE 6

7. Advantages and disadvantages of hydrogen electrode Advantages It can be used for a range of pH values. The standard hydrogen electrode potential is zero. Therefore, the electrode potential of another electrode can be easily calculated. Disadvantages Platinum is expensive and platinized platinum is difficult to prepare . Maintaining the pressure of hydrogen and the concentration of acid is not easy. It isn't easy to obtain pure hydrogen. 20XX PRESENTATION TITLE 7

8. Why hydrogen electrode is used as the reference electrode ? Hydrogen is the element with least atomic number(1) and atomic mass(~1).So hydrogen ions (H+) and its element H 2 gas combined standard electrode potential (SEP) is arbitrarily assumed as 0.0 Volt at STP (Standard Temperature Pressure), though it's not equal to zero but has some value that's impossible to measure. 20XX PRESENTATION TITLE 8

9. THANK YOU Shekhor Imtiaj Jumman 20XX PRESENTATION TITLE 9