JEE Mains 2026 April 5 Shift 2 Chemistry Answer Key Error

Update: NTA Releases Final Answer Key for April 5 Shift 2

✔ NTA's final answer key has corrected every single question Cracku's analysis had flagged. The final key, released on the NTA portal, revises the answers to 19 of the 25 Chemistry questions for April 5 Shift 2 — the exact 19 questions Cracku identified as discrepancies in the provisional key.

All 19 corrections are inside the Chemistry section. Mathematics and Physics answer keys remained unchanged, confirming Cracku's earlier verification that those sections were correct. On 17 of the 19 revised Chemistry questions, NTA's final answer matches Cracku's independently verified answer exactly. On the remaining 2 (Q691121506 and Q691121507), NTA picked a different option from Cracku's verified answer — both of which differ from the original provisional key.

NTA's 19 Corrections (Provisional → Final)

Impact: Scores for every student who appeared in April 5 Shift 2 will be recalculated by NTA against the corrected key. Students should expect their Chemistry section marks, overall score, percentile, and All India Rank to all be revised upward once the final result is published. The Cracku JEE Mains Score Calculator already reflects the NTA final key — paste your response sheet to see the updated score.

JEE Mains 2026 April 5 Shift 2 Chemistry Overview

The JEE Mains 2026 April 5 Shift 2 paper is drawing attention due to an unusual drop in Chemistry scores, with the average at just 6.4 marks, compared to 26–35 marks in other shifts.

Data from Cracku’s JEE Mains Score Calculator shows that while Physics and Maths remain normal, only Chemistry has sharply declined indicating this is not a tough paper or weak performance issue, but likely a problem with the NTA provisional JEE answer key.

Cracku experts re-analysed all 25 Chemistry questions and found that around 76% of answers (19/25) do not match the official key, across both MCQs and numerical questions.

Overall, the pattern clearly points to a Chemistry answer key discrepancy, not an actual drop in student performance.

JEE Mains 2026 Chemistry Average by Shift (Session 2 Analysis)

This insight is driven as much by data from the JEE Mains 2026 Score Calculator as by the answer key analysis itself. As thousands of April 5 Shift 2 response sheets were uploaded, the Chemistry average dropped to just 6.4 marks far lower than any other shift in Session 2.

The JEE Mains shift-wise analysis dashboard, which compares subject averages across all April shifts, instantly flagged this as a clear outlier, highlighting a likely Chemistry answer key discrepancy rather than a performance issue.

Why April 5 Shift 2 Chemistry Scores Are Extremely Low

Also Read, JEE Mains 2026 Marks vs Percentile vs Rank

JEE Mains 2026 April 5 Shift 2 Subject-wise Analysis (Physics vs Maths vs Chemistry)

Every aspirant takes all three subjects  Maths, Physics, Chemistry  in the same shift. So the cohort, paper-setting rigour, test-day stamina, and exam-centre conditions are identical across subjects. When only Chemistry collapses while the other two subjects stay within their usual band, the cause is very unlikely to be "a hard paper" or "a weak cohort"  both of those would have dragged all three subject averages down together.

Apr 5 Shift 2 Physics is tracking at 37.0 and Maths at 17.3  numbers in line with the broader Session 2 distribution. Chemistry is the clear outlier. That pattern is the classic signature of an answer key or data issue localised to one section rather than a test-day problem.

JEE Mains 2026 Answer Key Error in Chemistry

• On 19 of the 25 Chemistry questions (~76%), the most-popular student response on the Cracku score calculator differs from the answer published in the NTA provisional key.
• On the 5 numerical Chemistry questions, fewer than 6% of students arrived at the answer printed in the NTA key compared to 30–50% accuracy on numericals in every other Session 2 shift.
• On the Equilibrium question (Q6 in most paper versions), roughly 57% of students chose Option 2 while the NTA key indicates Option 3.
• The discrepancy is spread across the paper it is not concentrated in the hardest questions or the numerical section alone.

Collectively, this pattern is what a key mismatch looks like statistically: the correct textbook answers agree with where students are clustering, and the published key sits off-centre.

How Cracku Identified the Chemistry Answer Key Discrepancy

This pattern was first spotted through the aggregate data flowing into the Cracku JEE Mains Score Calculator. With response sheets from thousands of Apr 5 Shift 2 aspirants, the Chemistry average came in at a flat 6.4 — five times lower than every other shift.

From there, Cracku's Chemistry faculty independently re-solved all 25 Chemistry questions for this shift:

1. Each question was re-solved step-by-step using standard NCERT and reference textbook methods.
2. Solutions were cross-referenced with NTA's question paper PDF to ensure no transcription error.
3. Our verified answer was compared against the answer in the NTA provisional key.
4. The same process was repeated, as a control, for the Maths and Physics sections of the same shift.

Outcome: the Maths and Physics keys for April 5 Shift 2 were verified as correct. The Chemistry section had 19 instances where the published key answer does not match the verified correct answer.

Also Read, JEE Mains 2026 Answer Key

Worked Examples

Example 1 — Stoichiometry (Limiting Reagent)

Question: What volume of hydrogen gas at STP would be liberated by the action of 50 mL of H₂SO₄ of 50% purity (density = 1.3 g mL^-1) on 20 g of zinc?

Step-by-step:

• Mass of H₂SO₄ available = 50 × 1.3 × 0.5 = 32.5 g → 32.5 / 98 = 0.332 mol
• Moles of Zn = 20 / 65 = 0.308 mol → Zn is the limiting reagent
• From Zn + H₂SO₄ → ZnSO₄ + H₂: moles of H₂ = 0.308
• Volume at STP = 0.308 × 22.4 = 6.892 L

NTA provisional key indicates: 8.375 L. This would require more H₂ than the limiting reagent (Zn) can stoichiometrically produce.

Example 2 — Equilibrium Constant

Question: For A(g) ⇌ B(g) + C(g), the initial amount of A is 'a'. At equilibrium, A remaining = (a−x) and total pressure = p. Find K_p.

Derivation:

• Total moles at equilibrium = (a−x) + x + x = a + x
• Mole fractions: x_A = (a−x)/(a+x); x_B = x_C = x/(a+x)
• K_p = (P_B · P_C) / P_A = [x² / (a²−x²)] · p

NTA provisional key indicates: (a²−x²)/x² · p — this is the reciprocal (K_p for the reverse reaction).

Example 3 — Chemical Kinetics (Numerical)

Question: For the reaction A → P, the graph of t_1/2 vs [A]₀ is linear. At [A]₀ = 4×10^-3, t_1/2 = 240 s. Find x = t_1/2 at [A]₀ = 1.5×10^-3.

Reasoning:

• t_1/2 ∝ [A]₀ → zero-order reaction
• For a zero-order reaction: t_1/2 = [A]₀ / (2k)
• x / 240 = 1.5 / 4 → x = 90 s

NTA provisional key indicates: 2 s.

JEE Mains 2026 April 5 Shift 2 Question-wise Answer Key Comparison

• Maths: Challenging but answer key independently verified as correct. Average ~17.3.
• Physics: Standard difficulty, answer key verified as correct. Average ~37.0.
• Chemistry: The outlier. If the discrepancy on 19 of 25 questions holds after the NTA challenge window, students will have effectively lost ~25–30 Chemistry marks on average just from key-level errors  independent of their actual preparation.

Impact of Wrong Answer Key on JEE Percentile & Rank

JEE Main percentiles are normalised within each shift, so an answer key error inside a single shift does not drag percentiles across the country but it heavily compresses them within that shift. Apr 5 Shift 2 aspirants currently appear with collapsed Chemistry raw scores, which means:

• Percentiles calculated off the provisional key understate the actual performance distribution for this shift.
• If NTA accepts challenges and corrects the Chemistry key, section scores for this shift jump and the percentile curve shifts upward.
• Final All India Ranks (AIR) will be recalculated off the corrected key expected around April 20, 2026.

Until then, students from this shift should not make admission or JoSAA strategy decisions based on the current provisional percentile.

Use the Cracku JEE Mains Score Calculator

The Cracku JEE Mains Score Calculator lets you paste your NTA response sheet URL and get your raw score, section-wise accuracy, and expected percentile instantly. It is the same tool that first surfaced the Apr 5 Shift 2 Chemistry anomaly  because thousands of aspirants were using it, the aggregate picture became visible in real time.

Using the JEE Mains 2026 Score Calculator is super simple. Just follow these steps:

• Step 1: Open the official NTA response sheet
• Step 2: Copy your response sheet URL
• Step 3: Paste the URL into Cracku’s JEE Mains Score Calculator
• Step 4: Click on “Calculate Score”
• Step 5: Instantly view:
• • Your raw score
  • Section-wise accuracy (Physics, Chemistry, Maths)
  • Expected percentile & rank

JEE Mains 2026 Apr 5 Shift 2 Chemistry Answer Key Error: Conclusion

Cracku's analysis of JEE Main 2026 April 5 Shift 2 has identified discrepancies in 19 of the 25 Chemistry answers in the NTA provisional answer key, producing a Chemistry shift average of just 6.4 marks an outlier unmatched in Session 2. The Maths and Physics keys for this shift have been verified and are correct. Aspirants from this shift should use the Cracku JEE Mains Score Calculator to verify their answers, and file objections before the April 13, 2026 NTA challenge deadline. Cracku will update the calculator and the analysis dashboard as soon as NTA releases the final answer key.