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JEE Main: Did These Questions Have Wrong Answers In JEE Main Answer Key?
Updated on May 05, 2022 08:57 AM IST | #JEE Main
The Joint Entrance Examination (JEE) Main is conducted by the National Testing Agency (NTA), and every year, lakhs of students appear for the exam. It is the entrance test – or the preliminary selection round – for the top engineering colleges in the country including the Indian Institutes of Technology (IIT), National Institutes of Technology (NIT), Indian Institutes of Information Technology (IIIT) and many more government institutions.
Clearly, JEE Main is critical. However, JEE Main 2021 had questions which were conceptually or factually ambiguous and some of them were simply incorrect, going by the JEE Main answer key. Last year, the exam was conducted in four phases – February, March, July and August – across 26 Shifts. The result was declared in September.
Here, Careers360 looks into the questions asked in the July and August shifts, and highlights some of the errors in the JEE Main previous year question paper’s Chemistry section. The necessary changes required for these questions were absent from the NTA JEE Main answer keys, which could have affected the scorecards of many candidates in the JEE Main result.
These questions, along with their respective problems, are listed out below:
JEE Main 2021: Attempt 3
July 20, Shift 1
Question ID : 86435117255
JEE Main Answer Key: 172
The issue:
The unit in which Kp is to be reported has not been specified in the question.
So, a student solving for the unit as (Pa)-1 will get an answer of 0.172 which would be rounded off to 0 while the given answer will be in units of (kPa)-1
____________________________________________________________________________
July 20, Shift 2
Question ID : 86435117528
JEE Main Answer Key: 1
The issue:
There is a conceptual error in the question. A negatively-charged sol cannot be precipitated by a negatively-charged ion.
Also, the coagulating value is defined as the minimum concentration of an electrolyte in millimoles per litre required to cause precipitation of a sol in two hours.
So, there arises another problem: How do you extrapolate data for two hours from the one-hour data?
____________________________________________________________________________
July 22, Shift 2
Question ID : 86435117785
JEE Main Answer Key: 86435159952 (Option 2)
Question and Option IDs
The issue:
Multiple options given in the question (Options 1,2 and 3) are capable of forming tertiary alcohol on reaction with excess of Grignard reagent (CH3MgBr) followed by hydrolysis.
Option 1: Alpha- Beta unsaturated carbonyl compounds show direct addition to the carbonyl group with Grignard reagent. Hence, tertiary alcohols will be obtained from the carbonyl groups
Option 3: Grignard reagent can add to a ketone, forming a tertiary alcohol.
____________________________________________________________________________
July 25, Shift 1
Question ID : 86435118234
JEE Main Answer Key: 86435161299 (Option 1)
The issue:
Lewis acids are not used with Phenol because Phenol itself forms a complex with the Lewis acid, due to which the ring becomes deactivated towards Electrophilic Substitution.
In fact, this reaction of Phenol with a Lewis acid FeCl3 is actually used to detect the presence of Phenol in solution. Phenol forms a complex with neutral FeCl3 and produces a violet colour.
Correct answer should be 86435161298 [Option (3)]
____________________________________________________________________________
July 25, Shift 1
Question ID : 86435118225
JEE Main Answer Key: 86435161264 (Option 3)
The issue:
Be is not an alkaline earth metal as its oxide and hydroxide are Amphoteric in nature.
Here is an excerpt from NCERT textbook’s chapter on the s Block elements confirming it.
Hence, Statement I is also correct in the given question.
Correct answer should be 86435161261 [Option (2)]
____________________________________________________________________________
July 27, Shift 1
Question ID : 86435118870
JEE Main Answer Key: 5
The issue:
Data given is insufficient to solve the problem.
Molality (m) can be calculated from the density of solution only when the Molarity (M) is also given in the question.
In the question, Molarity has not been provided and thus the question cannot be solved.
____________________________________________________________________________
July 27, Shift 2
Question ID : 86435119236
JEE Main Answer Key: 300
The issue :
The answer in the JEE Main final answer key was wrong. The answer should have been 600.
____________________________________________________________________________
JEE Main 2021: Attempt 4
August 26, Shift 2
Question ID : 86435120226
JEE Main Answer Key: 50
The issue :
The answer given in the answer key is wrong. The answer should be 0.
The answer is 0.02 which would be rounded off to 0.
For the answer to be 50, the value of (Kc)-1 had to be asked.
____________________________________________________________________________
August 27, Shift 1
Question ID : 86435120586
JEE Main Answer Key: 4
The issue :
The answer given is 4 because the inner 4f electrons have not been counted.
The question does not say that we need to consider only the 5f electrons
____________________________________________________________________________
August 31, Shift 2
Question ID : 86435121290
JEE Main Answer Key: 86435170463 (Option 4)
The issue :
Alcoholic NaOH causes dehydrohalogenation (elimination) and not substitution.
The answer should be 86435170462 (Option 2)
____________________________________________________________________________
August 31, Shift 2
Question ID : 86435121287
JEE Main Answer Key: 86435170452 (Option 2)
The issue :
None of the options is correct.
All the given options contain permanganate ion (MnO4-) which contains Mn in its highest oxidation state (+7) and hence, it cannot show disproportionation reaction
Question should have been awarded as bonus
____________________________________________________________________________
September 1, Shift 2
Question ID : 86435121562
JEE Main Answer Key: 86435171281 (Option 4)
The issue :
Options 1 and 4 can both be correct but only Option 4 has been given as the correct answer.
Acenaphthene (compound in Option 1) is also Aromatic in nature.
____________________________________________________________________________
Apart from the above-mentioned questions, there were also some in the integer section that had very lengthy mathematical calculations and whose answers had to be rounded off to the nearest integers.
These questions are usually solved by approximations and it is very difficult for students to arrive at the correct integer answer. Previously, these questions had a correct range for the answer, which gave students some leeway to make appropriate approximations in calculations.
Now, with negative marking in the numerical response questions, this becomes an even bigger problem. Considering the high-stakes nature of the JEE Mains, even a few such errors can have significant ramifications for applicants and be deeply demoralising.
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Aug 06, 2025
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Questions related to JEE Main
Have a question related to JEE Main ?
To apply for JEE Mains 2026 you need to go through online application process that is conducted by NTA(National Testing Agency). Here's a guide along with documents:
1) Register yourself on the official website https://jeemains.nta.nic
2) Fill up the application form with the details written on it.
3) Upload the documents, here's a list of required documents:
- passport size photograph with your name and date written on it
- Signature on white paper
- class 10th certificate
- category certificate if you're not from general
- Adress proof and a Valid ID proof
4) Pay the application fees and download your confirmation application
Important: Application form is expected to open in December 2025 as for season 1 and also in February 2026 as for season 2. So apply accordingly when you are ready to give your 100% in exam.
Babita Rawat 06 August,2025
Hello Erlina
The application window of JEE Mains 2026 for the 1st attempt (Jan 2026) is likely to open in November 2025 or early December 2025 and last for 3-4 weeks.
The application window of JEE Mains 2026 for the 2nd attempt (April 2026) is likely to open in February 2025 or March 2025.
To know more about JEE Mains 2026: JEE Mains 2026 by CAREERS360
Hope this answer helps! Thank You!!!
Yash Teotia 06 August,2025
For the top 20 percentile eligibility in JOSAA counselling, the category that is used is based on what you declare in your JEE Mains application and for which you provide a valid certificate during document verification not necessarily the one mentioned in your board exam. Since you're from Maharashtra and appeared under SEBC, you’ll be treated as a General category candidate unless you have a valid central OBC NCL certificate.
So for JOSAA, they’ll consider your category only if it’s valid under the central category list and matches what you declared in JEE Mains along with the correct certificate. The SEBC category used in the MH board won’t be considered by JOSAA unless it overlaps with central OBC NCL.
Chelsie G 05 August,2025
With 79 percentile in JEE Main, NITs/IIITs are unlikely, but you can target top private engineering colleges in Karnataka like RVCE, BMSCE, MSRIT, PES University, and DSCE through COMEDK or management quota.
You have a good chance for branches like ECE, Mechanical, or Civil. For CSE or AI/ML, management quota is the best route. Consider KCET counselling if you're a Karnataka student.
Abhilasha Agrawal 04 August,2025
With a 79 percentile in JEE Main, your rank would be around 2.2–2.4 lakhs, which may not fetch top NITs but is still decent for several good private engineering colleges in Karnataka. You can consider colleges like Dayananda Sagar College of Engineering, NIE Mysore, JSS Science & Technology University, CMRIT, NMIT, and MSRIT (for non-CSE branches or through spot/management rounds). These colleges often accept students with JEE scores for some quota or have their own counseling/admission process. If you’re flexible with branches and can apply early, you’ll still have a good chance at getting into solid colleges with decent infrastructure and placement support.
Rithwik Kumar Sahu 04 August,2025
Popular JEE Main Questions
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