HS 2nd year Chemistry Unit 2: Electrochemistry

 

🔹 Topic: Electrochemical Cells

Q1. What is an electrochemical cell?
Answer:
An electrochemical cell is a device that converts chemical energy into electrical energy through a redox reaction.

Keywords with Bengali Meaning:

• Electrochemical cell – ইলেক্ট্রোকেমিক্যাল কোষ

• Chemical energy – রাসায়নিক শক্তি

• Electrical energy – বৈদ্যুতিক শক্তি

• Redox reaction – রিডক্স বিক্রিয়া

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🔹 Topic: Galvanic Cells (Voltaic Cells)

Q2. What is a galvanic cell? Give an example.
Answer:
A galvanic cell is an electrochemical cell in which a spontaneous redox reaction produces electrical energy. Example: Daniell Cell.

Keywords with Bengali Meaning:

• Galvanic cell – গ্যালভানিক কোষ

• Spontaneous reaction – স্বতঃস্ফূর্ত বিক্রিয়া

• Daniell Cell – ড্যানিয়েল কোষ

Q3. What is a salt bridge and what is its function?
Answer:
A salt bridge is a U-shaped tube containing a gel permeated with an inert electrolyte. It maintains electrical neutrality in the cell by allowing the flow of ions.

Keywords:

• Salt bridge – লবণ সেতু

• Inert electrolyte – নিষ্ক্রিয় ইলেক্ট্রোলাইট

• Electrical neutrality – বৈদ্যুতিক নিরপেক্ষতা

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🔹 Topic: Electrode Potential

Q4. What is standard electrode potential?
Answer:
Standard electrode potential is the potential of a half-cell under standard conditions (1 M concentration, 1 atm pressure, 25°C) when connected to a standard hydrogen electrode.

Keywords:

• Electrode potential – ইলেক্ট্রোড পটেনশিয়াল

• Standard conditions – মানক অবস্থা

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🔹 Topic: Nernst Equation

Q5. State the Nernst Equation and its significance.
Answer:
The Nernst equation is:
$E_{cell} = E^o_{cell} - \frac{0.0591}{n} \log Q$
It relates the cell potential to the standard electrode potential and the concentration of the ions involved.

Keywords:

• Nernst Equation – নের্নস্ট সমীকরণ

• Cell potential – কোষের বিভব

• Concentration – ঘনত্ব

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🔹 Topic: Conductance of Electrolytic Solutions

Q6. Define conductivity and molar conductivity.
Answer:

• Conductivity (κ) is the conductance of a solution per unit length and area.

• Molar conductivity (Λm) is the conductivity of an electrolytic solution divided by its concentration.

Keywords:

• Conductivity – পরিবাহিতা

• Molar conductivity – মোলার পরিবাহিতা

• Electrolyte – ইলেক্ট্রোলাইট

Q7. What is the effect of dilution on conductivity and molar conductivity?
Answer:
On dilution, conductivity decreases but molar conductivity increases, especially for weak electrolytes due to increased ionization.

Keywords:

• Dilution – পাতলা করা

• Ionization – আয়নায়ন

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🔹 Topic: Electrolytic Cells and Electrolysis

Q8. What is electrolysis?
Answer:
Electrolysis is the process of bringing about a chemical change using electricity in an electrolytic cell.

Keywords:

• Electrolysis – ইলেক্ট্রোলাইসিস

• Electrolytic cell – ইলেক্ট্রোলাইটিক কোষ

Q9. State Faraday’s laws of electrolysis.
Answer:

1. The mass of substance liberated at an electrode is proportional to the quantity of electricity passed.

2. The masses of different substances liberated by the same quantity of electricity are proportional to their equivalent weights.

Keywords:

• Faraday’s laws – ফ্যারাডের সূত্র

• Equivalent weight – সমতুল্য ওজন

• Quantity of electricity – বিদ্যুতের পরিমাণ

📘 Worksheet: Chapter 2 – Electrochemistry

Subject: Chemistry | Class: 12 | Chapter: Electrochemistry
Instructions: Answer the following questions in the space provided. Meanings of important keywords are also given for your reference.

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1. Define an electrochemical cell.

🔑 Keywords:

• Electrochemical cell – ইলেক্ট্রোকেমিক্যাল কোষ

• Chemical energy – রাসায়নিক শক্তি

• Electrical energy – বৈদ্যুতিক শক্তি

• Redox reaction – রিডক্স বিক্রিয়া

Answer:

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2. What is a galvanic cell? Give one example.

🔑 Keywords:

• Galvanic cell – গ্যালভানিক কোষ

• Spontaneous reaction – স্বতঃস্ফূর্ত বিক্রিয়া

• Daniell Cell – ড্যানিয়েল কোষ

Answer:

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3. What is a salt bridge and what is its function?

🔑 Keywords:

• Salt bridge – লবণ সেতু

• Inert electrolyte – নিষ্ক্রিয় ইলেক্ট্রোলাইট

• Electrical neutrality – বৈদ্যুতিক নিরপেক্ষতা

Answer:

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4. Define standard electrode potential.

🔑 Keywords:

• Electrode potential – ইলেক্ট্রোড পটেনশিয়াল

• Standard conditions – মানক অবস্থা

Answer:

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5. Write the Nernst Equation. What does it tell us?

🔑 Keywords:

• Nernst Equation – নের্নস্ট সমীকরণ

• Cell potential – কোষের বিভব

• Concentration – ঘনত্ব

Answer:

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6. Define conductivity and molar conductivity.

🔑 Keywords:

• Conductivity – পরিবাহিতা

• Molar conductivity – মোলার পরিবাহিতা

• Electrolyte – ইলেক্ট্রোলাইট

Answer:

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7. What is the effect of dilution on conductivity and molar conductivity?

🔑 Keywords:

• Dilution – পাতলা করা

• Ionization – আয়নায়ন

Answer:

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8. What is electrolysis?

🔑 Keywords:

• Electrolysis – ইলেক্ট্রোলাইসিস

• Electrolytic cell – ইলেক্ট্রোলাইটিক কোষ

Answer:

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9. State Faraday’s laws of electrolysis.

🔑 Keywords:

• Faraday’s laws – ফ্যারাডের সূত্র

• Equivalent weight – সমতুল্য ওজন

• Quantity of electricity – বিদ্যুতের পরিমাণ

Answer:

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