CBSE Class 10 General: CBSE Class 10 and 12 Practical Exams 2026 – New Pattern, Marking Scheme, and Preparation Tips

For students preparing under CBSE Class 10 General curriculum guidelines, the CBSE Class 10 and 12 Practical Exams 2026 represent a vital component of the overall board evaluation. Accounting for 20% of total marks in Class 10 and up to 30% in Class 12 science streams, practical assessments test hands-on experimental proficiency, conceptual clarity, and analytical application. The Central Board of Secondary Education (CBSE) has updated protocols for the 2026 practical examinations to emphasize competency-based evaluations, transparent digital marking, and standardized viva voce assessments.

Key Changes and Examination Pattern for CBSE Practicals 2026

The 2026 practical exam framework introduces structural refinements designed to eliminate discrepancies in internal scoring while ensuring strict adherence to NCERT laboratory curricula across affiliated schools.

• Standardized Dual-Examiner Protocol (Class 12): Every practical batch in Class 12 is evaluated jointly by an appointed External Examiner and an Internal Examiner. For Class 10, assessments are conducted by an internal subject committee following standardized board rubrics.
• Real-Time Digital Marks Uploading: Schools are mandated to upload practical marks on the official CBSE Pariksha Sangam portal on the same day the evaluation takes place.
• Geo-Tagged Photographic Evidence: Laboratory sessions require mandatory geo-tagged group photographs of the exam batch along with the internal and external examiners to authenticate examination integrity.
• Strict Competency-Based Viva Voce: Viva questions in 2026 are aligned with core application principles rather than rote memorization of definitions.

Evaluation Blueprint and Marking Schemes

Class 10 Science Practical and Internal Assessment (20 Marks)

Class 10 Science does not involve external examiners; instead, schools conduct continuous comprehensive assessments totaling 20 marks:

• Periodic Tests (5 Marks): Average of the best two periodic written assessments conducted across the academic session.
• Multiple Assessments (5 Marks): Quizzes, oral tests, concept maps, and classroom observation activities.
• Subject Enrichment / Practical Lab Work (5 Marks): Performance of prescribed NCERT lab experiments, maintenance of the lab record notebook, and viva voce.
• Portfolio / Student Notebooks (5 Marks): Organization, neatness, completion of assignments, and self-assessment sheets.

Class 12 Science Stream Practical Blueprint (30 Marks)

For subjects such as Physics, Chemistry, and Biology, the 30-mark evaluation is strictly categorized as follows:

• Two Experiments (7 + 7 = 14 Marks): One experiment selected from Section A and one from Section B of the NCERT laboratory manual.
• Practical Record File (5 Marks): Certified documentation of at least 12–15 prescribed experiments and 6 activities performed over the session.
• Investigatory Project File (3 Marks): Independent experimental or observational project report submitted by the candidate.
• Viva Voce (5 Marks): Oral evaluation covering performed experiments, underlying theoretical principles, and the investigatory project.
• One Experimental Activity / Spotting (3 Marks): Demonstration of a minor activity or slide identification.

Core Practical Concepts and Analytical Methodologies

1. Physics: Electrical Resistance and Verification of Ohm's Law

In both Class 10 Science and Class 12 Physics, the relationship between electric potential difference ($V$) and electric current ($I$) across an ideal ohmic conductor is fundamental:

Mathematical Formulation:

$$V = I \cdot R \implies R = \frac{V}{I}$$

Where $V$ is measured in volts ($\text{V}$), $I$ in amperes ($\text{A}$), and $R$ represents resistance in ohms ($\Omega$).

• Circuit Configuration: The ammeter is always connected in series to capture total branch current (low internal resistance), while the voltmeter is connected in parallel across the resistance wire (high internal resistance).
• Error Minimization: Students must inspect the instruments for zero error ($e_0$) and apply proper zero correction before recording deflections: $\text{Corrected Reading} = \text{Observed Reading} - e_0$.

2. Chemistry: Volumetric Redox Titration ($KMnO_4$ vs. Mohr's Salt)

A benchmark Class 12 practical involves the standardization of potassium permanganate ($KMnO_4$) against standard ferrous ammonium sulfate (Mohr's salt, $\text{FeSO}_4\cdot(\text{NH}_4)_2\text{SO}_4\cdot 6\text{H}_2\text{O}$):

Ionic Equation:

$$\text{MnO}_4^- + 8\text{H}^+ + 5\text{Fe}^{2+} \longrightarrow \text{Mn}^{2+} + 5\text{Fe}^{3+} + 4\text{H}_2\text{O}$$

• Self-Indicator Action: $KMnO_4$ serves as its own indicator; the end point is marked by the persistent appearance of a permanent pale pink color.
• Medium Control: Dilute $\text{H}_2\text{SO}_4$ is used to provide the acidic medium. Hydrochloric acid ($\text{HCl}$) cannot be used because $KMnO_4$ oxidizes $\text{Cl}^-$ to chlorine gas ($\text{Cl}_2$), leading to erroneous titre values.

Important CBSE Practical Exam and Viva Voce Questions with Answers

Question 1 (Class 10 Science): What is the physiological significance of using potassium hydroxide ($KOH$) in the experiment demonstrating carbon dioxide release during respiration?

Answer: Potassium hydroxide ($KOH$) pellets or solution act as a chemical absorbent for carbon dioxide ($\text{CO}_2$). In the closed conical flask containing germinating seeds, $KOH$ absorbs the $\text{CO}_2$ released during aerobic respiration:

$$2KOH + CO_2 \longrightarrow K_2CO_3 + H_2O$$

This absorption creates a partial vacuum (lowered atmospheric pressure) inside the conical flask, causing water in the connected delivery tube beaker to rise, visually confirming respiration.

Question 2 (Class 10 Science): Differentiate between saponification and esterification reactions encountered in organic chemistry practicals.

Answer:

• Esterification: An acid-catalyzed reaction between a carboxylic acid and an alcohol yielding a sweet-smelling ester and water:
  $$\text{CH}_3\text{COOH} + \text{C}_2\text{H}_5\text{OH} \xrightarrow{\text{Conc. } \text{H}_2\text{SO}_4} \text{CH}_3\text{COOC}_2\text{H}_5 + \text{H}_2\text{O}$$
• Saponification: The alkaline hydrolysis of an ester (or vegetable oil/fat) with sodium hydroxide to regenerate the alcohol and produce a sodium salt of the fatty acid (soap):
  $$\text{CH}_3\text{COOC}_2\text{H}_5 + \text{NaOH} \longrightarrow \text{CH}_3\text{COONa} + \text{C}_2\text{H}_5\text{OH}$$

Question 3 (Class 12 Physics): Why is a null deflection method preferred over direct deflection measurements in a Meter Bridge or Potentiometer experiment?

Answer: The null deflection method (Wheatstone bridge principle) measures balance conditions where zero current flows through the galvanometer ($I_g = 0$). Because no current is drawn from the source at balance point, measurement errors arising from the internal resistance of the cell, connecting wire resistances, and meter loading effects are eliminated, yielding high precision.

Question 4 (Class 12 Chemistry): In salt analysis, why is it necessary to boil off $\text{H}_2\text{S}$ gas before proceeding from Group II to Group III cation analysis?

Answer: Hydrogen sulfide ($\text{H}_2\text{S}$) is a reducing agent. In Group III analysis, iron is precipitated as ferric hydroxide ($\text{Fe(OH)}_3$) using $\text{NH}_4\text{OH}$ in the presence of $\text{NH}_4\text{Cl}$. If $\text{H}_2\text{S}$ is not boiled off completely, it reduces $\text{Fe}^{3+}$ back to $\text{Fe}^{2+}$, which fails to precipitate completely in Group III, leading to false negatives.

Question 5 (General Viva Voce): What is parallax error, and how is it eliminated when taking optical bench readings?

Answer: Parallax error is the apparent shift in the relative position of an object (or optical pin) with respect to an image when the observer moves their eye sideways. It occurs when the object pin and the real image formed by the lens/mirror do not occupy the exact same plane in space. It is eliminated by adjusting the position of the search pin until the tip of the image and the tip of the pin remain in continuous contact without separating as the eye moves from left to right.

Actionable Preparation Strategy to Secure 100% Practical Marks

1. Complete and Certified Record Files: Ensure that your practical record notebook and investigatory project files are neatly bound, indexed, and signed by your subject teacher well before January 2026.
2. Master Circuit and Ray Diagrams: Draw neat, labeled circuit diagrams and optical ray paths with accurate directional arrows. In practical exams, marks are deducted for inverted diode connections or missing ray direction arrows.
3. Understand Systematic Tabulation: Memorize the observation tables for standard experiments. Record measurements with appropriate decimal precision matching the least count of the instrument (e.g., $0.01\text{ cm}$ for Vernier calipers, $0.001\text{ cm}$ for screw gauges).
4. Prepare Viva Voce Fundamentals: Revisit theoretical derivations behind every apparatus. Examiners frequently ask for unit conversions, definitions of standard constants, and reasons for experimental precautions.

Where to Practice More

Excelling in the CBSE Class 10 and 12 Practical Exams 2026 requires consistent alignment between laboratory observations and theoretical concepts. For comprehensive CBSE Class 10 and Class 12 chapter-wise question banks, previous year question papers with step-by-step marking schemes, and customized board practice tests, visit qptool.theorify.in to strengthen your exam readiness and achieve top scores.