Question

Mark Whether are True of False

1. Indicator electrodes are typically made from relatively inert metals and they work best when the electrode surface is large and clean

2. Platinum electrodes are more inert than and gold electrodes.

3. KCl is often used as an electrolyte for salt bridge, for the purpose to reduce junction potentials between salt bridges and the electrolyte solutions in cells.

4. Standard conditions for reduction potential’s is 25 °C and  = 1 for all aqueous species.

5. Reduction potentials are measured relative to the standard hydrogen electrode (S.H.E)

6. E^ofor the S.H.E is defined at 0 volts.

7. pH meter measures the solution of pH, based on the boundary potential that is built off when the pH probe is inserted into the sample solution and does not involve any redox reactions

8. LaF₃a water-soluble crystal, can be used to prepare an electrochemical cell for measuring fluoride anion concentration

9. Electrolytic cell is different from galvanic and cell. The former is to use electricity to drive redox reactions while the latter uses redox reactions to generate electricity.

10. Selectivity of electrochemical method for blood glucose level modern comes from in the enzymatic reaction.

Answer 1

1. Indicator electrodes are inert , they do not take part in titrations. They work best when surface area is small so that the electrode canot change the concentration of analyte. Hence the statement is false

2. Platinum is less reactive and more inert than gold. Hence the statement is true.

3.Liquid junction potental is the difference of potential tgat devlops at the junction when two solutions of different concentrations comes in contact.

In salt bridge KCl is used to connect the two solutions in the half cells. KCl practically counter balanced the potential difference between two solutions hence liquid junction potential is almost nil. So the statement is true.

4.

Standard condition means all species are in standard state , for aqueous species at standard condition 25⁰c and 1 M concentration . statement is true.

5. The potentials of other electrodes are represented as reference to the standard hydrogen electeode.For this S.H.E. is connected with any other single electrode and the potential of the galvanic cell is calculated. The e.m.f of the cell = difference of the two electrode as S.H.E. is zero.

Both standard reduction and oxidation potential can measured by usinf a S .H.E

Hence the statement is true.

6. The standard hydrogen electrode consists os pur hydrogen gas (adsorbed by platinum black) at 1 atm pressure is emersed in solution of H⁺ ion of unit activity .The potential of this electrode is zero at all temperature. The given statement is true.

7.pH meter is used to measure the potential difference across the membrane . This difference is proportional to pH of the solution. This statement is true.

8. LaF₃ is used as an electrode for measuring F^- concentration , but it is insoluble in water , Hence statement is false.

9.

Statement is true. Galvanic cell uses spontaneous redox reaction to produce electricity

whereas electrical energy is use to drive a nonspontaneous reaction .

10.

measurement of Blood glucose are based on the interactions of enzymes. The enzymes are hexokinase, glucose oxidase and glycise-1-dehydrogenase . Their redox reactions are totally diffetent. Aming them glucose oxidase is most sensitive. Hence selectivity of electrochemical method for blood glucose level modern comes from in the enzymatic reaction. The statement is true.