Bihar Board Class 11 Half Yearly Chemistry Question Paper 2025-26 PDF with Solutions

Bihar Board Class 11 Half-Yearly Chemistry Exam 2025-26 Overview

Important highlights of BSEB Class 11 half-yearly chemistry exam 2025-26 are given below:

Bihar Board Class 11 Half-Yearly Chemistry Question Paper 2025-26

For the academic session 2025-2026, the Bihar Board Class 11 Half Yearly Chemistry Examination was scheduled in the second sitting on 19th September 2025 between 2:00 PM and 5:15 PM, which is over now. Students will be able to download the BSEB Class 11 half-yearly question paper 2025-26 from this page. Students are advised to keep an eye on this page to get early access to the question paper.

Bihar Board Class 11 Half-Yearly Chemistry Answer Key 2025-26

Students can also match the correct answer from the Bihar Board class 11 half-yearly chemistry answer key 2025-26 PDF, which is provided here. The BSEB class 11 half-yearly chemistry answer key will help to analyse the topics in which students are struggling, so they can work and improve in the upcoming exam.

1. Define limiting reagent.

Answer:
The limiting reagent is the reactant which is completely consumed first in a chemical reaction and limits the amount of product formed.

2. Define law of conservation of mass.

Answer:
The law of conservation of mass states that mass is neither created nor destroyed in a chemical reaction; the total mass of reactants is equal to the total mass of products.

3. What is the difference between molar mass and molecular mass?

4. What is mole fraction?

Answer:
The mole fraction of a component in a mixture is the ratio of the number of moles of that component to the total number of moles of all components.

$
\text { Mole fraction }=\frac{\text { Moles of a component }}{\text { Total moles of mixture }}
$

5. State Bohr's quantization condition.

Answer:
According to Bohr, the angular momentum of an electron revolving in an atom is quantized and is given by:

$
m v r=\frac{n h}{2 \pi}, \quad n=1,2,3, \ldots
$

6. What is meant by an orbit in Bohr’s model?

Answer:
An orbit is a fixed circular path around the nucleus in which an electron revolves with definite energy.

7. What are quantum numbers?

Answer:
Quantum numbers are a set of numbers used to describe the energy, position, and orientation of an electron in an atom.

8. Define the Pauli exclusion principle.

Answer:
The Pauli exclusion principle states that no two electrons in an atom can have the same set of four quantum numbers.

10. What is the Aufbau principle?

Answer:
The Aufbau principle states that electrons fill the orbitals in order of increasing energy, i.e., the lower energy orbitals are filled first before higher energy orbitals.

Bihar Board Class 11 Half-Yearly Chemistry Question Paper Analysis

Students can check the detailed analysis of the BSEB class 11 half-yearly chemistry question paper 2025-26, which is given below.

• Overall Level: Moderate, NCERT-based and fairly construed for students.
• Major Question Types: Definitions and laws, Bohr model, thermodynamics, chemical equilibrium, periodicity.
• Numericals: Fewer numbers and largely formula-based and easy.
• Questions were mostly asked from the Mole concept & basic laws, Structure of atom (Bohr model & quantum numbers), Periodicity (atomic radius, electronegativity, diagonal relationship) and Thermodynamics, chemical equilibrium.
• Conceptual vs. Memory-Based: Mostly conceptual (~60%), definitions/laws (~40%)

Also Check- Bihar Board Class 11 Half-Yearly Question Paper 2025-26