Re NEET 2026: 30 Tough Questions That Troubled Most Aspirants in the Exam

Re-NEET 2026: Why Some Questions Were Difficult

Not all difficult questions are based on advanced concepts. In the Re-NEET 2026 exam, many questions challenged the students because of:

• Multiple concepts are involved in a single question

• Confusing statement-based formats

• Lengthy calculations

• NCERT line interpretation

• Similar-looking answer choices

• Time-consuming diagrams and data analysis

Students who maintained an overall accuracy and avoided panic were generally able to perform better than others on such questions.

Re-NEET 2026 Difficulty Level Overview

Here is a quick overview of the Re-NEET 2026 difficulty level.

30 Questions That Troubled Most Re-NEET 2026 Aspirants

Here is a detailed analysis of the top 30 questions that troubled Re-NEET 2026 aspirants the most.

Most Challenging Physics Questions in Re-NEET 2026

Physics emerged as the most time-consuming section for many candidates in Re-NEET 2026. Several questions required multi-step calculations, strong conceptual understanding, and the application of formulas from multiple chapters. The following Physics questions were reported by students and experts as the most challenging and time-intensive in the exam.

Q1. A photon and an electron, each of $20\ \text{eV}$ energy, move in free space. The ratio of linear momentum of electron $P_e$ to that of photon $P_{ph}$ is:

(Take speed of light $= 3\times10^8\ \text{m s}^{-1}$, charge of electron $= -1.6\times10^{-19}\ \text{C}$ and mass of electron $= 9\times10^{-31}\ \text{kg}$)

(1) 275

(2) $\frac{2}{450}$

(3) $\frac{1}{250}$

(4) 225

Why tricky: Students use $p = mv$ for both, but photon momentum is $p = \frac{E}{c}$ while electron momentum is $p = \sqrt{2mE}$ — two completely different formulas, and eV-to-joule conversion must be done carefully.

Q2. A long solenoid of length $l$ and radius $r$. If $n$ is the number of turns per unit length and $\mu_0$ is the permeability of free space, the inductance of the solenoid is:

(1) $2\mu_0\pi n^2r^2l$

(2) $\mu_0\pi n^2r^2l$

(3) $\mu_0n^2r^2l$

(4) $\left(\frac{\mu_0}{2\pi}\right)n^2r^2l$

Why tricky: The standard formula is $L = \mu_0n^2\pi r^2l$, but options are designed to confuse by misplacing $\pi$.

Q3. A thin horizontal disc is rotating about a vertical axis passing through its fixed centre $O$. Its angular momentum is $L_A$ and $L_B$ computed about points $A$ and $B$ respectively, with $OB = 2\times OA$. The value of $\frac{L_A}{L_B}$ is:

(1) 2

(2) $\frac{1}{4}$

(3) $\frac{1}{2}$

(4) 1

Why tricky: Angular momentum of a rigid body about its own rotation axis is fixed ($L = I\omega$) and does not change with the reference point on the axis.

Q4. Consider two circuits (A) and (B), each having two resistors. One of them has a positive temperature coefficient of resistance $+\alpha$, while the other has a negative temperature coefficient $-\alpha$. The current through these circuits are denoted by $I_A$ and $I_B$. At the initial temperature, the resistance of both resistors is $R_0$. As the temperature is increased, the correct option that describes the variation of current in these circuits is:

(1) Both $I_A$ and $I_B$ remain constant

(2) $I_A$ remains constant while $I_B$ increases

(3) $I_A$ decreases while $I_B$ increases

(4) $I_A$ increases while $I_B$ decreases

Why tricky: Students must analyse both series and parallel configurations separately and determine how the net resistance changes with temperature.

Q5. An AC voltage $V = 220\sin(2\times10^3t)\ \text{Volt}$ is applied to a series LCR circuit. Then the current amplitude in this circuit is:

(Given: $L = 10\ \text{mH}$, $C = 25\ \mu\text{F}$, $R = 100\ \Omega$)

(1) $22.0\ \text{A}$

(2) $2.2\ \text{A}$

(3) $5.5\ \text{A}$

(4) $11.0\ \text{A}$

Why tricky: Students must first identify $\omega = 2\times10^3\ \text{rad s}^{-1}$, calculate $X_L$ and $X_C$, check resonance, and then determine the impedance.

Q6. The temperature of a metallic sphere of radius $R$ is increased by a small amount $\Delta T$. If the linear coefficient of thermal expansion of the metal is $\alpha$, the approximate increase in the volume of the sphere is:

(1) $6\pi R^3\alpha\Delta T$

(2) $2\pi R^3\alpha\Delta T$

(3) $3\pi R^3\alpha\Delta T$

(4) $4\pi R^3\alpha\Delta T$

Why tricky: Students must remember that the volumetric expansion coefficient is $\gamma = 3\alpha$ and use $\Delta V = \gamma V\Delta T$.

Q7. In an adiabatic expansion, the temperature of one mole of an ideal monatomic gas ($\gamma = \frac{5}{3}$) decreases from $60\ \text{K}$ to $50\ \text{K}$. The work done by the gas in the process is:

(Take the universal gas constant as $R = 8.3\ \text{J mol}^{-1}\text{K}^{-1}$)

(1) $166\ \text{J}$

(2) $41.5\ \text{J}$

(3) $83\ \text{J}$

(4) $124.5\ \text{J}$

Why tricky: Students must use $W = \frac{nR(T_1-T_2)}{\gamma-1}$ and correctly substitute $\gamma-1=\frac{2}{3}$.

Q8. Two planets $P_1$ and $P_2$ with equal mass have radii $R_1$ and $R_2$ respectively, where $R_2 = 2R_1$. The escape speeds of $P_1$ and $P_2$ are $v_1$ and $v_2$ respectively. Then $\frac{v_1}{v_2}$ is:

(1) 2

(2) $\frac{1}{\sqrt{2}}$

(3) 1

(4) $\sqrt{2}$

Why tricky: Escape velocity is given by $v = \sqrt{\frac{2GM}{R}}$, so $v \propto \frac{1}{\sqrt{R}}$.

Q9. A unit positive point charge is taken slowly through an infinitesimally thin tube inside a charged dielectric sphere of radius $R$ having uniform positive charge density $\rho$. The initial and final positions of the charge are at distances $2R$ and $3R$ respectively from the centre of the sphere. The magnitude of the total work done on the point charge is $\frac{\pi\rho R^2}{n\varepsilon_0}$. The value of $n$ is:

(1) 18

(2) 2

(3) 6

(4) 9

Why tricky: Students must apply the electric potential formula outside a uniformly charged sphere and substitute $Q = \rho\left(\frac{4}{3}\pi R^3\right)$ correctly.

Q10. An electromagnetic wave travelling in a lossless dielectric medium having dielectric constant $\varepsilon_r = 9$ has the electric field:

$E = E_0\sin(kz - 2\pi\times10^6 t)$

Among the following, the incorrect statement is:

(1) The direction of propagation of the electromagnetic wave is along $+z$

(2) The speed of the electromagnetic wave inside the medium is $10^8\ \text{m s}^{-1}$

(3) The electromagnetic wavelength inside the medium is $300\ \text{m}$

(4) The magnetic field is given by $B_y = \left(\frac{B_0}{\sqrt{\varepsilon_r}}\right)\sin(kz - 2\pi\times10^6 t)$ where $v$ is the speed of the electromagnetic wave inside the medium.

Why tricky: Students who do not carefully analyse wave speed, wavelength, and field amplitude relations in a dielectric medium are likely to choose the incorrect option.

Check Re NEET 2026 Physics answer key with Solutions for better analysis and practice

Top Chemistry Questions That Troubled Re-NEET 2026 Aspirants

Chemistry featured a mix of conceptual, reaction-based, and calculation-intensive questions in Re-NEET 2026. Several questions tested candidates' understanding of Organic, Physical, and Inorganic Chemistry simultaneously, making them difficult to solve within a limited time. The following Chemistry questions were identified by students and experts as the most challenging.

Q1. Consider the following reaction, and choose the correct option:

A toluene compound undergoes reaction with:

i. $CrO_2Cl_2,\ CS_2$

ii. $H_3O^+$

to give compound $P$.

(1) Compound $P$ is obtained by the hydrogenation of benzoyl chloride with Pd on $BaSO_4$

(2) On treating compound $P$ with saturated $NaHCO_3$ solution, brisk effervescence is observed

(3) Compound $P$ can be prepared by treating benzene with anhydrous $AlCl_3$ and $CH_3COCl$

(4) On treatment with bromine water, compound $P$ gives a white precipitate

Why Students Found It Difficult: $CrO_2Cl_2$ (Etard reaction) converts toluene into benzaldehyde. Many candidates confused the product with benzoic acid and incorrectly evaluated the statements. Option (2) acted as a major trap because aldehydes do not react with $NaHCO_3$, whereas carboxylic acids do.

Q2. The lanthanide ion having four unpaired electrons is:

(Given: Atomic numbers of Ce = 58, Nd = 60, Tb = 65 and Ho = 67)

(1) $Ho^{3+}$

(2) $Nd^{3+}$

(3) $Ce^{3+}$

(4) $Tb^{3+}$

Why Students Found It Difficult: Students had to determine the electronic configuration of each lanthanide ion after removal of three electrons and then count unpaired $4f$ electrons correctly. Miscounting the occupancy of $f$ orbitals often led to incorrect answers.

Q3. For an elementary chemical reaction, the Arrhenius plot is given below. If the energy of activation is $6.64\ \text{kJ mol}^{-1}$ and $R = 8.3\ \text{J K}^{-1}\text{mol}^{-1}$, the temperature at which the rate constant becomes $e^2\ \text{min}^{-1}$ is:

(1) $250\ \text{K}$

(2) $125\ \text{K}$

(3) $150\ \text{K}$

(4) $200\ \text{K}$

Why Students Found It Difficult: Candidates needed to extract the pre-exponential factor from the Arrhenius plot and then use $k = Ae^{-E_a/RT}$ by working backwards. The graphical interpretation combined with calculations increased the difficulty level.

Q4. The green paramagnetic species formed by heating $KMnO_4$ at $513\ \text{K}$ is:

(1) $KO_2$

(2) $K_2MnO_4$

(3) $Mn_3O_4$

(4) $MnO$

Why Students Found It Difficult: Many students confused the products formed during thermal decomposition of $KMnO_4$. The green colour clue pointed towards $K_2MnO_4$, but candidates often selected more familiar manganese oxides.

Q5. Given below are two statements:

Statement I: trans-But-2-ene upon treatment with $Br_2$ in $CCl_4$ gives the following product.

Statement II: cis-But-2-ene upon treatment with alkaline $KMnO_4$ gives the following product (meso diol).

(1) Both Statement I and Statement II are correct

(2) Both Statement I and Statement II are incorrect

(3) Statement I is incorrect but Statement II is correct

(4) Statement I is correct but Statement II is incorrect

Why Students Found It Difficult: This question tested stereochemistry and the distinction between anti-addition and syn-addition. Candidates who confused the stereochemical outcomes of bromination and hydroxylation frequently selected the wrong option.

Q6. Given below are two statements:

Statement I: Heating concentrated $H_2SO_4$ and $MnO_2$ results in oxidation of Mn.

Statement II: Heating $NaI$ with concentrated $H_2SO_4$ and $MnO_2$ results in reduction of Mn.

Choose the most appropriate answer from the options given below:

(1) Statement I is incorrect but Statement II is correct

(2) Both Statement I and Statement II are correct

(3) Both Statement I and Statement II are incorrect

(4) Statement I is correct but Statement II is incorrect

Why Students Found It Difficult: The question required careful tracking of oxidation states. Many candidates reversed oxidation and reduction processes while analysing the role of manganese in the reactions.

Q7. Among the following electron gain enthalpy trend options, the correct trend is:

(1) $I > Br > Cl > F$

(2) $F > Cl > Br > I$

(3) $Br > Cl > F > I$

(4) $Cl > F > Br > I$

Why Students Found It Difficult: Students often confused electron gain enthalpy with electronegativity trends. The exceptional behaviour of fluorine due to its very small size makes chlorine exhibit a more negative electron gain enthalpy.

Q8. Given below are two statements:

Statement I: $[Fe(ox)_3]^{3-}$ is chiral.

Statement II: trans-$[Cr(H_2O)_4(ox)_2]^-$ is chiral.

(Given: $oxH_2 = HOOC-COOH$)

Choose the most appropriate answer from the options given below:

(1) Statement I is incorrect but Statement II is correct

(2) Both Statement I and Statement II are correct

(3) Statement I is correct but Statement II is incorrect

(4) Both Statement I and Statement II are incorrect

Why Students Found It Difficult: The question tested stereoisomerism in coordination compounds. Candidates had to identify symmetry elements correctly and determine whether the complexes exhibited optical activity.

Q9. The correct statement about peptides and proteins is:

(1) In $\alpha$-helices, the polypeptide chain is twisted into a left-handed helix through intramolecular hydrogen bonds

(2) Tertiary structure of proteins has two or more polypeptide subunits

(3) Only the quaternary proteins having a biological structure are active

(4) In $\beta$-pleated sheet structures, peptide chains are held together by intermolecular hydrogen bonds

Why Students Found It Difficult: All options appeared conceptually similar. The question required a precise understanding of primary, secondary, tertiary and quaternary structures of proteins and their associated bonding patterns.

Q10. $2A \xrightarrow{k} B$ is a zero-order reaction, where the rate of disappearance of $A$ is $2\ \text{M min}^{-1}$. If the initial concentration of $A$ is $1.0\ \text{mol L}^{-1}$, then the time taken to complete $75%$ of the reaction will be:

(1) $2.0\ \text{min}$

(2) $1.5\ \text{min}$

(3) $0.75\ \text{min}$

(4) $1.0\ \text{min}$

Why Students Found It Difficult: Many candidates overlooked the stoichiometric coefficient in $2A \rightarrow B$. Correct interpretation of the reaction rate and application of the zero-order integrated rate law were both necessary to reach the right answer.

Also Check: Re NEET 2026 Chemistry Question Paper with Solutions

Most Challenging Biology Questions in Re-NEET 2026

Although Biology was considered relatively easier than Physics and Chemistry, several questions tested candidates' conceptual clarity, NCERT understanding, and attention to detail. The following Biology questions were identified by students and experts as the most confusing in Re-NEET 2026.

Q1. Which of the following statements is incorrect?

(1) Fibrinogen is produced from fibrinogen injury

(2) Blood coagulates in response to an injury

(3) Blood clot consists of fibrins

(4) Fibrin is produced from fibrinogen

Why students found it difficult: All four options contain closely related terms such as fibrin and fibrinogen. Many candidates misread the statements and confused the roles of fibrin and fibrinogen during blood clotting.

Q2. How many molecules of pyruvic acid are produced at the end of glycolysis from 206 molecules of glucose?

(1) 412

(2) 206

(3) 103

(4) 309

Why students found it difficult: Although glycolysis is a basic concept, the unusual number 206 caused many students to overthink the question. Candidates who forgot that one glucose molecule yields two pyruvate molecules often selected trap options.

Q3. Which of the following is incorrect about the reabsorption process in Henle's loop?

(a) The descending limb of Henle's loop is permeable to water but almost impermeable to electrolytes

(b) Urine gets concentrated in the ascending limb of Henle's loop

(c) Reabsorption of $Na^+$ and water takes place in Henle's loop

(d) Active or passive transport of electrolytes occurs in the ascending limb

(1) (a), (b) and (d) only

(2 (a) and (b) only

(3) (b) and (c) only

(4) (a), (b) and (c) only

Why students found it difficult: This question required simultaneous evaluation of multiple statements. Many candidates mixed up the permeability characteristics of the ascending and descending limbs of Henle's loop.

Q4. Given below are two statements:

Statement I: Modern Homo sapiens arose around 75000 to 10000 years ago.

Statement II: Homo sapiens arose in Australia and moved across continents.

Choose the most appropriate answer from the options given below:

(1) Statement I is incorrect but Statement II is correct

(2) Both Statement I and Statement II are correct

(3) Both Statement I and Statement II are incorrect

(4) Statement I is correct but Statement II is incorrect

Why students found it difficult: Students often remembered only parts of human evolution. The incorrect origin of Homo sapiens in Statement II and the questionable timeline in Statement I created confusion.

Q5. Mitochondrial inner membrane encloses ________:

(1) aqueous humor

(2) matrix

(3) cytosol

(4) mucous

Why students found it difficult: The word "encloses" acted as the key trap. Students frequently confused the matrix, intermembrane space, and outer membrane regions of the mitochondrion.

Q6. Which of the following statements about the lac-operon is correct?

(1) Galactose can act as an inducer of lac operon

(2) Gene $i$ is constitutively expressed

(3) Lactose activates repressor to bind to the operator

(4) Genes $i$, $z$, $y$ and $a$ share a single common promoter

Why students found it difficult: The question tested fine details of the lac operon. Candidates often confused lactose with allolactose and were unsure whether the regulator gene shared the same promoter as the structural genes.

Q7. Which of the following is not correct about Plasmodium?

(1) Fertilization takes place in mosquito gut

(2) Gametes develop in RBCs

(3) Reproduces sexually in liver cells

(4) Gametocytes develop in mosquito gut

Why students found it difficult: The life cycle of Plasmodium involves multiple stages in both human and mosquito hosts. Students often mixed up where gametes, gametocytes and sexual reproduction occur.

Q8. Given below are two statements:

Statement I: Down's syndrome is caused by the absence of one of the X-chromosomes.

Statement II: Turner's syndrome is caused by the presence of an additional copy of the chromosomes.

Choose the most appropriate answer from the options given below:

(1) Both Statement I and Statement II are incorrect

(2) Both Statement I and Statement II are correct

(3) Statement I is incorrect but Statement II is correct

(4) Statement I is correct but Statement II is incorrect

Why students found it difficult: The disorders were deliberately interchanged. Candidates who remembered only the names of the syndromes without their chromosomal basis often selected the wrong option.

Q9. Which of the following hormones is not secreted by the human placenta?

(1) LH

(2) hCG

(3) Estrogen

(4) Progesterone

Why students found it difficult: All four hormones are associated with pregnancy and reproduction. Students frequently confused placental hormones with pituitary hormones, particularly LH and hCG.

Q10. Given below are two statements:

Statement I: In gymnosperms, the male and female gametophytes remain within the sporangia.

Statement II: In gymnosperms, seeds are not covered.

Choose the most appropriate answer from the options given below:

(1) Statement I is incorrect but Statement II is correct

(2) Both Statement I and Statement II are correct

(3) Both Statement I and Statement II are incorrect

(4) Statement I is correct but Statement II is incorrect

Why students found it difficult: Both statements are correct, but many students confused gymnosperms with angiosperms and overlooked the retention of gametophytes within the sporangia.

Check Here: ReNEET 2026 Biology Question Paper with Solutions

Common Mistakes Students Made While Attempting Difficult Questions

Many candidates lost marks due to avoidable mistakes rather than lack of preparation. Some of the most common errors included:

• Spending too much time on a single question

• Misreading NCERT-based statements and keywords

• Confusing similar concepts and terms

• Ignoring hidden traps in questions

• Making calculation errors under pressure

• Overthinking straightforward questions

Strong conceptual clarity, careful reading, and effective time management are essential for improving accuracy and maximising scores in competitive exams like NEET.

What Future NEET Aspirants Can Learn from Re-NEET 2026

The biggest lesson from Re-NEET 2026 is that conceptual knowledge and clarity matter more than completing the syllabus and learning without proper clarity. Students who understood the logic behind the questions were able to perform better while solving the unfamiliar questions.