CELL IN CHEMISTRY (Electrochemical Cell)

byhomeacademy •مايو 20, 2026

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⚗️ CELL IN CHEMISTRY (Electrochemical Cell)

🔹 What is a Cell?

In chemistry, a cell is a device that converts chemical energy into electrical energy (or vice versa) through redox reactions.

👉 Also called an Electrochemical Cell

🔋 Types of Electrochemical Cells

1. Galvanic Cell (Voltaic Cell)

Converts chemical → electrical energy
Reaction is spontaneous

👉 Example: Daniell Cell

2. Electrolytic Cell

Converts electrical → chemical energy
Reaction is non-spontaneous

👉 Example: Electrolysis of water

⚡ Basic Components (Elements of Cell)

1. Anode

Oxidation takes place

Loss of electrons
In galvanic cell: Negative electrode

👉 Trick: AN-OX (Anode = Oxidation)

2. Cathode

Reduction takes place

Gain of electrons
In galvanic cell: Positive electrode

👉 Trick: RED-CAT (Reduction = Cathode)

3. Electrolyte

Substance that conducts electricity

Contains ions (e.g., NaCl solution)

4. Salt Bridge

Maintains electrical neutrality

Contains KCl / KNO₃

👉 Prevents charge buildup

5. External Circuit

Path for electron flow

Wire + voltmeter

⚙️ Working of Daniell Cell

👉 Reaction:

Zn → Zn²⁺ + 2e⁻ (Oxidation)

Cu²⁺ + 2e⁻ → Cu (Reduction)

👉 Overall Reaction:
Zn + Cu²⁺ → Zn²⁺ + Cu

📊 Cell Representation

Zn | Zn^{2+} || Cu^{2+} | Cu

👉 Left = Anode
👉 Right = Cathode

🔑 Important Points for Exams

✔ Electron flows from Anode → Cathode
✔ Current flows from Cathode → Anode
✔ Salt bridge prevents polarization
✔ EMF (Electromotive force) = Potential difference

📝 MCQ Questions (Chemistry Cell)

Q1. In a galvanic cell, oxidation occurs at:

A. Cathode
B. Anode
C. Electrolyte
D. Salt bridge
✅ Answer: B

Q2. Which electrode is positive in galvanic cell?

A. Anode
B. Cathode
C. Both
D. None
✅ Answer: B

Q3. Function of salt bridge is:

A. Increase voltage
B. Allow electron flow
C. Maintain neutrality
D. Produce ions
✅ Answer: C

Q4. Electron flow is from:

A. Cathode → Anode
B. Anode → Cathode
C. Electrolyte → Anode
D. Salt bridge → Cathode
✅ Answer: B

Q5. In electrolytic cell, anode is:

A. Positive
B. Negative
C. Neutral
D. None
✅ Answer: A

📊 Statement-Based Questions

Q1. Consider the following:

Oxidation occurs at anode
Cathode is negative in galvanic cell
Electrons flow from anode to cathode

A. 1 and 3
B. 2 and 3
C. 1 and 2
D. All

✅ Answer: A

Q2. Which are correct?

Salt bridge maintains electrical neutrality
Reduction occurs at cathode
Anode is always positive

A. 1 and 2
B. 2 and 3
C. 1 and 3
D. All