Salt Bridge and Its Function in Electrochemical Cells

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What is the purpose of connecting the electrode to another half-cell of known potential when measuring potential difference?

To increase the voltage output of the cell
To transfer electrons between the two half-cells
To establish a reference point for potential measurement (correct)
To create a closed circuit for electrons to flow

In a cell diagram, how is the hydrogen electrode represented?

Pt |H2 (g) | H+ (aq) (correct)
H2 (g) | Pt electrode
H2 (g) | H+ (aq)
Metal electrode e.g. Fe

Why are standard conditions necessary for a reference electrode like the standard hydrogen electrode?

To increase the voltage output of the cell
To minimize the effect of temperature changes on potential readings
To prevent the flow of electrons in the cell
To maintain the same redox equilibrium position for accurate potential measurement (correct)

What happens to the potential of an electrode if the concentration of metal ions in solution increases?

The potential becomes more positive (B) Signup and view all the answers

Which component is NOT required for a standard hydrogen electrode to function as a reference electrode?

Metal electrode such as Fe (A) Signup and view all the answers

What is the purpose of using a platinum wire coated in finely divided platinum in electrode potential measurements?

To act as a catalyst because it is porous and can absorb hydrogen gas (C) Signup and view all the answers

In the context of electrode potential measurements, what does SHE stand for?

Standard Hydrogen Electrode (C) Signup and view all the answers

What are the standard conditions required for electrode potential measurements?

All ion solutions at 1.00 mol dm-3, gases at 100 kPa pressure, and no current flowing (C) Signup and view all the answers

Which electrode system is connected to the hydrogen electrode system to measure standard electrode potential?

Platinum electrode with Fe2+/Fe3+ ions (A) Signup and view all the answers

How are standard electrode potentials typically quoted in data books?

With the more reduced form on the left side of the equation (D) Signup and view all the answers

What does the potential difference (E) of +1.1V for the given cell indicate?

The zinc half-cell has more tendency to oxidize to Zn2+ and release electrons compared to the copper half-cell. (C) Signup and view all the answers

Why is a high resistance voltmeter used when measuring potential difference in an electrochemical cell?

To measure the maximum possible potential difference (E). (D) Signup and view all the answers

What is the purpose of a salt bridge in an electrochemical cell?

To balance the charge in the two half-cells and complete the circuit. (B) Signup and view all the answers

Which electrode in the given cell is considered the negative terminal?

Zinc electrode (D) Signup and view all the answers

What happens when a very high resistance voltmeter is used during potential difference measurement in an electrochemical cell?

The maximum possible potential difference (E) can be measured accurately. (A) Signup and view all the answers

What type of electrode must be used in a system that does not include a metal that can act as an electrode?

Platinum electrode (D) Signup and view all the answers

In the cell diagram, how are H+ ions and H2O treated when the system contains multiple species?

They can be left out (B) Signup and view all the answers

What is used to separate different physical states in a half equation?

Vertical line ( | ) (A) Signup and view all the answers

In the context of electrode potential measurement, why is it not possible to measure the absolute potential of a half electrode on its own?

Lack of reference point (A) Signup and view all the answers

What is the purpose of the salt bridge in a cell diagram?

To establish ionic connection between half cells (D) Signup and view all the answers

What is usually used to make a salt bridge in an electrochemical cell?

Piece of filter paper soaked in a salt solution (D) Signup and view all the answers

Why is potassium chloride not suitable for copper systems in a salt bridge?

It forms complexes with chloride ions (C) Signup and view all the answers

Why is a wire not used as a salt bridge in an electrochemical cell?

It sets up its own electrode system (D) Signup and view all the answers

In an electrochemical cell, what happens when the voltmeter is replaced with a bulb or if the circuit is short-circuited?

The reactions occur separately at each electrode (A) Signup and view all the answers

Which electrode always undergoes reduction in an electrochemical cell?

The most positive electrode (D) Signup and view all the answers

Which type of cells are non-rechargeable due to having non-reversible reactions?

Primary cells (B) Signup and view all the answers

What is the overall reaction for the primary Lithium–manganese dioxide cell?

Li+aq + MnO2 (s) +e- → LiMnO2(s) (D) Signup and view all the answers

In a lead-acid cell, what is the half-reaction that occurs during discharge?

PbSO4 + 2e- → Pb + SO42- (A) Signup and view all the answers

What is the standard electrode potential for the half-reaction: Zn2+(aq) + 2e- → Zn(s)?

-0.76 V (C) Signup and view all the answers

What components are present in the conventional cell diagram for the Lithium-manganese dioxide cell?

What is the equation used to calculate the EMF of a cell?

Ecell = Erhs - Elhs (B) Signup and view all the answers

Which half cell has a standard electrode potential value of -2.37V?

Mg2+ (aq) | Mg(s) (A) Signup and view all the answers

Which direction does the more negative half cell in a redox reaction tend to proceed?

Oxidize (go backwards) (B) Signup and view all the answers

What is the electrode potential for the half equation: Fe2+(aq) + 2e- → Fe(s)?

-0.44V (D) Signup and view all the answers

Which electrode will reduce and go from left to right in a redox reaction?

Fe(s) (D) Signup and view all the answers

In a spontaneous change, what is the value of Ecell typically?

Positive (A) Signup and view all the answers

Which equation would you use to calculate the Ecell for a spontaneous change?

Ecell = Ered – Eox (A) Signup and view all the answers

What happens in the reaction: Zn2+(aq) + 2e- → Zn(s)?

Reduction (A) Signup and view all the answers

What is the standard electrode potential for Cu2+ (aq) | Cu (s)?

+0.34V (A) Signup and view all the answers

Electrode Connection Purpose

Provides a reference point for potential measurements.

Hydrogen Electrode Representation

Pt | H2 (g) | H+ (aq)