12th Chemistry Chapter 2 – 5 Mark Questions (Important & Repeated – TN Board)
Prepare for exams with 12th Chemistry Chapter 2 (p-Block Elements-I) important 5 mark questions. This collection includes most repeated and previously asked questions based on TN Board exams, helping students revise key concepts quickly and score better.
p-Block Elements-I – 5 Mark Questions
Most Repeated 5 Marks
Note : Number next to questions tells, how many times it has been repeated in past few years
1.Describe the structure of diborane? (5)
- In diborane two BH2 units are linked by two bridged hydrogens.
- Therefore, it has eight B-H bonds.
- The four terminal B-H bonds are normal covalent bonds (two centre – two electron bond or 2c-2e bond).
- The remaining four electrons have to be used for the bridged bonds. i.e. two three centred B-H-B bonds utilise two electrons each.
- Hence, these bonds are three centre- two electron bonds (3c-2e).
- The bridging hydrogen atoms are in a plane.
- In diborane, the boron is sp3 hybridised.
- Three of the four sp3 hybridised orbitals contains single electron and the fourth orbital is empty.
- Two of the half filled hybridised orbitals of each boron overlap with the 1s orbitals of two hydrogens to form four terminal 2c-2e bonds, leaving one empty and one half filled hybridised orbitals on each boron.
- The Three centre – two electron bonds, B-H-B bond formation involves overlapping the half filled hybridised orbital of one boron, the empty hybridised orbital of the other boron and the half filled 1s orbital of hydrogen.
2.Write a note on zeolites? (4)
- Zeolites are three-dimensional crystalline solids containing aluminium, silicon, and oxygen in their regular three dimensional framework.
- They are hydrated sodium alumino silicates with general formula Na2O.(Al2O3 ).x(SiO2 ).yH2O (x=2 to 10; y=2 to 6).
- Zeolites have a three dimensional crystalline structure looks like a honeycomb consisting of a network of interconnected tunnels and cages.
- Water molecules moves freely in and out of these pores but the zeolite framework remains rigid.
- Another special aspect of this structure is that the pore/channel sizes are nearly uniform, allowing the crystal to act as a molecular sieve.
12th Chemistry Chapter 2 Important 5 Marks Questions
Welcome to our collection of 12th Chemistry Chapter 2 Important 5 Marks Questions and Answers prepared from previous year public question papers and important repeated board exam questions. These long answer questions are highly useful for Tamil Nadu State Board Class 12 students preparing for public examinations, revision tests, and school examinations.
Chapter 2 contains several important theory-oriented and structure-based concepts that are frequently asked in Tamil Nadu board examinations. Practicing important 5 mark questions regularly helps students improve conceptual understanding, answer presentation skills, and confidence during examinations.
Most Repeated 5 Mark Questions
- Structure of Diborane
- Write a Note on Zeolites
Benefits of Practicing 5 Mark Questions
- Improves detailed answer writing skills
- Helps understand important concepts clearly
- Covers repeated public exam questions
- Enhances diagram and structure explanation skills
- Useful for board exam revision
Previous Year Public Exam Important Questions
The important 5 mark questions provided here are collected from previous year Tamil Nadu 12th Chemistry public question papers and important repeated board examination questions. Many of these long answer questions are frequently asked directly in public exams and school assessments.
Students are advised to practice writing answers with proper chemical equations, structures, diagrams, and important points to score maximum marks in the examination.
More 12th Chemistry Study Materials
Explore more useful Class 12 Chemistry study resources:
- Important 1 Mark Questions
- 2 Marks and 3 Marks Questions
- Book Back Answers
- Chapter Wise Notes
- Most Expected Questions
- Public Exam Study Materials
- Previous Year Question Papers with Answers
Regular revision of important 5 mark questions helps students improve confidence and score high marks in the 12th Chemistry public examination.
