AP Inter 1st Year Chemistry Answer Key 2026 LIVE: Unofficial Key by Subject Expert; Paper Difficulty LevelAP Inter 1st Year Chemistry Exam 2026 : Board of Intermediate Education, Andhra Pradesh successfully conducted the AP Inter 1st Year Chemistry Exam 2026 today, March 17, 2026. The exam started at 9 AM and wrapped up at 12 PM. It was of an Easy to Moderate difficulty level. The exam was held in offline mode and contained a total of 33 Very Short, Short, and Long Answer Questions. Section A was for 30 Marks, Section B was for 35 Marks, and Section C was for 20 Marks. Candidates can find the AP Inter 1st Year Chemistry Answer Key 2026 below. Along with it, an overview and analysis of the test has also been provided at a glance.
AP Inter 1st Year Chemistry Answer Key 2026 (Unofficial)
Here is the AP Inter 1st Year Chemistry Answer Key 2026:Question No. | Question | Correct Answer |
|---|---|---|
1 | The drug Azidothymidine (AZT) is used in the treatment of: | (2) AIDS |
2 | Which of the following is ionic? | (1) KI (Potassium Iodide) |
3 | The oxidation number of Sulphur in Na2S4O6 is: | (1) 2.5 (Average oxidation state) |
4 | Splitting of spectral lines in electric field is called | Stark effect |
5 | For an isolated system, ΔU=0, the value of ΔS will be | Positive (ΔS>0) |
6 | Ethyl alcohol and methyl alcohol can be separated by _____ method. | Fractional distillation |
7 | What is diagonal relationship? | The similarity in properties between certain elements of the second period and elements of the third period placed diagonally to them. |
8 | What is the value of Kw at 25°C? | 1.0×10−14 mol2L−2 |
9 | What is Lindlar's catalyst? | Palladized charcoal deactivated with poisons like quinoline or sulfur (used for partial hydrogenation of alkynes to cis-alkenes). |
11 | What is a black body? | An ideal body that absorbs and emits radiations of all frequencies perfectly. |
12 | Empirical formula CH2O, Mol. Mass 90. Calculate Molecular formula. | Empirical weight = 12+(2×1)+16=30.n=Empirical WeightMolecular Mass=3090=3.Molecular Formula = 3×(CH2O)=C3H6O3. |
13 | How many moles of glucose in 540 g of glucose? | Molar mass of glucose (C6H12O6) = 180 g/mol.Moles=Molar MassGiven Mass=180540=3 moles. |
14 | Name any two bridge elements. | Lithium (Li) and Beryllium (Be). (These are elements of the 2nd period that show similarities to elements of the next group in the 3rd period). |
15 | State the third law of thermodynamics. | The entropy of a perfectly crystalline substance approaches zero as the absolute temperature approaches zero (0 K). |
16 | What is heterogeneous equilibrium? Give two examples. | An equilibrium where the reactants and products are in different phases.1. CaCO3(s)⇌CaO(s)+CO2(g)2. H2O(l)⇌H2O(g) |
17 | Write the bond order and magnetic behaviour of H2. | Bond Order = 1.Magnetic behavior: Diamagnetic (all electrons are paired). |
18 | State Octet rule. | Atoms tend to gain, lose, or share electrons to have eight electrons in their outermost shell to achieve stability (like noble gases). |
19 | What is Wurtz' reaction? Give one example. | Alkyl halides react with sodium metal in dry ether to form higher alkanes.2CH3Br+2Nadry etherCH3−CH3+2NaBr |
20 | What is Friedel-Crafts alkylation? | The introduction of an alkyl group into a benzene ring using an alkyl halide in the presence of anhydrous AlCl3. |
21 | How many π and σ bonds in:(1) HC≡C−CH=CH−CH3(2) CH2=C=CH−CH3 | (1) 10 σ bonds, 3 π bonds.(2) 9 σ bonds, 2 π bonds. |
22 | What is carbocation? Give example. | A chemical species bearing a positive charge on a carbon atom. Example: Methyl carbocation (CH3+). |
23 | Write formulae for:(a) Nickel(II) sulphate(b) Thallium(I) sulphate | (a) NiSO4(b) Tl2SO4 |
Video - AP Inter 1st Year Chemistry Paper Solving 2026
AP Inter 1st Year Chemistry Exam Analysis 2026
AP Inter 1st Year Chemistry Exam 2026 Quick Facts
The following table displays the quick facts related to AP Inter 1st Year Chemistry Exam 2026:
Particulars | Details |
|---|---|
Name of the Exam | AP Intermediate 1st Year Chemistry |
Conducting Body | Board of Intermediate Education, Andhra Pradesh (BIEAP) |
Exam Date | March 17, 2026 |
Exam Time | 9 AM to 12 PM |
Exam Duration | 3 Hours |
Exam Mode | Offline (Pen and Paper) |
Question Paper Type | Very Short, Short, and Long Answer Questions |
Total Number of Questions | 33 Questions (Total including choice) |
Section-Wise Questions |
|
Total Marks | 85 Marks (Theory) (Total 109 inclusive of choice questions) |
Section-Wise Marks |
|
Marking Scheme |
|
Negative Marking | No Negative Marking |
Stay tuned to the LIVE blog for more updates on AP Inter 1st Year Chemistry Exam 2026 important topics and questions, topic-wise short notes.
AP Inter 1st Year Chemistry Exam 2026 LIVE
12 30 PM IST - 17 Mar'26
Exam Easy to Moderate
The exam was of an Easy to Moderate difficulty level! Students found Section A the easiest of all!
12 20 PM IST - 17 Mar'26
Answer key released
The AP Inter 1st Year Chemistry 2026 Answer Key has been released along with the exam analysis.
12 00 PM IST - 17 Mar'26
AP Inter 1st Year Chemistry Exam 2026: Exam Has Ended
The examination is over. Candidates are submitting their papers and moving out of the exam venue. We will collect the question paper, and formulate and provide the unofficial answer key on the page soon. The student reviews will also be collected and provided on the page. Stay tuned!
11 00 AM IST - 17 Mar'26
AP Inter 1st Year Chemistry Exam 2026: 1 Hour Left
Candidates now have 1 hour to submit their papers. The invigilator will collect the paper as soon as the final bell rings.
10 00 AM IST - 17 Mar'26
AP Inter 1st Year Chemistry Exam 2026: 1 Hour Over
1 Hour is over. Only 2 hours are left to finish the remaining paper.
09 00 AM IST - 17 Mar'26
AP Inter 1st Year Chemistry Exam 2026: Exam Starts
The exam has begun. Question papers have been circulated. Candidates have time till 12 PM to finish the paper.
08 00 AM IST - 17 Mar'26
AP Inter 1st Year Chemistry Exam 2026: Reporting Time
Candidates are reporting to the examination hall for the pre-verification process. Only those who clear the verification round will be allowed to appear for the test.
07 00 AM IST - 17 Mar'26
IUPAC Nomenclature of Organic Compounds
With more marks available, the complexity of IUPAC naming for polyfunctional organic compounds will likely increase. Ensure you have memorized the priority order of functional groups to correctly name complex hydrocarbons and aromatic compounds.
06 00 AM IST - 17 Mar'26
Short Note on p-Block – Group 13 Allotropy and Boranes
Boron exists in several allotropic forms and is known for forming electron-deficient compounds like Diborane (B_2H_6). Master the "banana bond" concept, where two electrons are shared between three centers (3c-2e), to secure marks in the short-answer section.
05 00 AM IST - 17 Mar'26
Important QnA 14 For Study
Question: Describe the bonding in Diborane (B_2H_6).
Answer: Diborane contains two types of hydrogen atoms: four terminal hydrogens involved in regular two-center, two-electron (2c-2e) bonds and two bridging hydrogens. The bridging hydrogens are involved in unique three-center, two-electron (3c-2e) bonds, also known as "banana bonds," which hold the two Boron atoms together.04 00 AM IST - 17 Mar'26
AP Intermediate 1st Year Chemistry Exam 2026: p-Block Elements – Group 13 and 14
Study the structure and properties of Borax and Diborane (B_2H_6), focusing on the unique "banana bonds" in the latter. For Group 14, understand the allotropy of Carbon (diamond, graphite, and fullerenes) and the industrial uses of Silicons.
03 00 AM IST - 17 Mar'26
AP Inter Chemistry Exam 2026: Short Note on s-Block – Diagonal Relationship of Li and Mg
Lithium and Magnesium show similar properties because of their comparable ionic sizes and high polarizing power (charge/radius ratio). Both form nitrides by direct reaction with air and have carbonates that decompose easily upon heating, unlike other alkali metals.
02 00 AM IST - 17 Mar'26
AP Inter First Year Chemistry Exam 2026: Important QnA 13 For Study
Question: Mention two reasons for the anomalous behavior of Lithium in Group 1.
Answer: Lithium behaves differently from other alkali metals due to its exceptionally small atomic and ionic size and its high polarizing power. These factors lead to increased covalent character in its compounds and a strong diagonal relationship with Magnesium.01 00 AM IST - 17 Mar'26
s-Block Elements – Alkali and Alkaline Earth Metals
Pay close attention to the anomalous behavior of Lithium and Beryllium compared to other members of their respective groups. The biological importance of Sodium, Potassium, Magnesium, and Calcium is a common 2-mark question topic.
12 00 AM IST - 17 Mar'26
Exam Today
BIEAP, Andhra Pradesh will conduct AP Inter First Year Chemistry Exam 2026 today, March 17 from 9 AM to 12 PM. Candidates will have to appear for the examination in offline mode.
11 00 PM IST - 16 Mar'26
Short Note on Hydrogen – Temporary vs. Permanent Hardness
Temporary hardness is caused by bicarbonates of Calcium and Magnesium and can be removed by simple boiling or Clark’s method (adding lime). Permanent hardness is caused by chlorides and sulfates and requires chemical treatments like the Permutit (Zeolite) process.
10 30 PM IST - 16 Mar'26
Important QnA 12 For Study
Question: What causes permanent hardness in water and how can it be removed using the Calgon method?
Answer: Permanent hardness is caused by the presence of soluble chlorides and sulfates of Magnesium and Calcium. In the Calgon method, sodium hexametaphosphate (Na_6P_6O_{18}) is added to the water, which reacts with the Calcium and Magnesium ions to form highly soluble complexes, preventing them from precipitating.10 00 PM IST - 16 Mar'26
AP Intermediate 1st Year Chemistry Exam 2026: Hydrogen and its Compounds
Ensure you can describe the preparation and properties of Hydrogen Peroxide (H_2O_2) and its role as both an oxidizing and reducing agent. Additionally, distinguish between temporary and permanent hardness of water and the methods used for their removal.
09 30 PM IST - 16 Mar'26
AP Inter Chemistry Exam 2026: Short Note on Ionic Equilibrium – Ostwald’s Dilution Law
This law states that the degree of dissociation (\alpha) of a weak electrolyte is inversely proportional to the square root of its molar concentration. It is applicable only to weak acids and bases and fails for strong electrolytes which dissociate completely.
09 00 PM IST - 16 Mar'26
AP Inter First Year Chemistry Exam 2026: Important QnA 11 For Study
Question: What is a buffer solution? Give an example of an acidic buffer.
Answer: A buffer solution is one that resists changes in pH when small amounts of an acid or base are added to it. An example of an acidic buffer is a mixture of a weak acid and its salt with a strong base, such as Acetic acid (CH_3COOH) and Sodium acetate (CH_3COONa).08 30 PM IST - 16 Mar'26
Ionic Equilibrium and Solubility Product
Focus on the concepts of pH, buffer solutions, and the Common Ion Effect as they are frequently tested in Very Short Answer Questions (VSAQs). The Solubility Product (K_{sp}) and its application in the qualitative analysis of salt are essential for the new pattern.
08 00 PM IST - 16 Mar'26
Short Note on Chemical Equilibrium – Equilibrium Constant (K_c)
The equilibrium constant is the ratio of the product of molar concentrations of products to those of reactants, each raised to the power of their stoichiometric coefficients. Note that pure solids and liquids are excluded from the K_c expression as their active mass is taken as unity.
07 30 PM IST - 16 Mar'26
Important QnA 10 For Study
Question: State Le Chatelier’s principle and its application to the synthesis of Ammonia.
Answer: If a system at equilibrium is subjected to a change in concentration, temperature, or pressure, the equilibrium shifts in a direction that tends to undo the effect of the change. In Haber’s process, high pressure and low temperature favor the production of ammonia because the forward reaction is exothermic and involves a decrease in the number of moles.07 00 PM IST - 16 Mar'26
AP Intermediate 1st Year Chemistry Exam 2026: Le Chatelier’s Principle and Chemical Equilibrium
Study the effect of change in concentration, temperature, and pressure on reversible reactions like the synthesis of Ammonia (Haber’s process). Understanding the equilibrium constant (K_c and K_p) relationship is also vital for the theoretical portion of Section B.
06 30 PM IST - 16 Mar'26
AP Inter Chemistry Exam 2026: Short Note on Thermodynamics – Gibbs Free Energy (\Delta G)
Gibbs Free Energy is the energy available to do useful work; if \Delta G is negative, the process is spontaneous. At equilibrium, \Delta G becomes zero, and this relationship is crucial for connecting thermodynamics with chemical equilibrium constants.
06 00 PM IST - 16 Mar'26
AP Inter First Year Chemistry Exam 2026: Important QnA 9 For Study
Question: How do Enthalpy (\Delta H) and Entropy (\Delta S) determine the spontaneity of a reaction?
Answer: A reaction is spontaneous if the change in Gibbs Free Energy (\Delta G) is negative, as determined by the equation \Delta G = \Delta H - T\Delta S. Spontaneity is favored by a decrease in enthalpy (exothermic) and an increase in the randomness or disorder (entropy) of the system.05 45 PM IST - 16 Mar'26
Hess’s Law of Constant Heat Summation
Hess’s Law is a staple for the 5-mark section, requiring you to explain that the total enthalpy change is independent of the pathway taken. Be prepared to solve thermochemical cycles where you calculate the heat of formation from given combustion data.
05 30 PM IST - 16 Mar'26
Short Note on Thermodynamics – State Functions and Path Functions
Properties like Internal Energy (U), Enthalpy (H), and Entropy (S) are state functions because they depend only on the initial and final states of the system. Heat (q) and Work (w), however, are path functions because their values vary depending on the route taken for the change.
05 15 PM IST - 16 Mar'26
Important QnA 8 For Study
Question: State and explain Hess’s Law of Constant Heat Summation.
Answer: Hess’s Law states that the total enthalpy change for a chemical reaction is the same regardless of whether the reaction occurs in one step or several steps. This law is a direct consequence of the first law of thermodynamics and allows the calculation of enthalpies that are difficult to measure directly.05 00 PM IST - 16 Mar'26
AP Intermediate 1st Year Chemistry Exam 2026: First and Second Laws of Thermodynamics
Master the concepts of Enthalpy (H), Entropy (S), and Gibbs Free Energy (G) to predict the spontaneity of a chemical reaction. The relation \Delta G = \Delta H - T\Delta S is a high-probability topic for short-answer questions in the 2026 exam.
04 45 PM IST - 16 Mar'26
AP Intermediate First Year Chemistry Exam 2026: Short Note on Stoichiometry – Oxidation Number Method
Balancing redox reactions requires assigning oxidation numbers to all elements and identifying the change in these numbers. Practice the step-by-step process of equating the total increase and decrease in oxidation numbers, especially in acidic and basic media.
04 30 PM IST - 16 Mar'26
AP Intermediate Chemistry Exam 2026: Important QnA 7 For Study
Question: What is the difference between an empirical formula and a molecular formula?
Answer: The empirical formula represents the simplest whole-number ratio of atoms of various elements present in a compound. The molecular formula shows the exact number of atoms of each element in a molecule and is calculated using the relation: \text{Molecular Formula} = n \times \text{Empirical Formula}.
04 15 PM IST - 16 Mar'26
Stoichiometry and Redox Reactions
The ability to balance redox reactions using the ion-electron method or the oxidation number method in both acidic and basic media is essential. Practice numericals involving limiting reagents and molarity/molality calculations to secure marks in Section B.
04 00 PM IST - 16 Mar'26
Short Note on States of Matter – Ideal Gas Equation
The ideal gas equation PV = nRT is a combination of Boyle's, Charles's, and Avogadro's laws. For numericals, ensure you use the correct value of R (Gas Constant) depending on whether the pressure is in atmospheres (0.0821) or SI units (8.314 \text{ J/mol K}).
03 45 PM IST - 16 Mar'26
Important QnA 6 For Study
Question: State Graham’s Law of Diffusion and provide its mathematical expression.
Answer: Graham’s Law states that at constant temperature and pressure, the rate of diffusion of a gas is inversely proportional to the square root of its density or molar mass. The formula is expressed as r_1/r_2 = \sqrt{M_2/M_1}.
03 30 PM IST - 16 Mar'26
AP Inter 1st Year Chemistry Exam 2026: Kinetic Molecular Theory of Gases
Revision should include the postulates of the Kinetic Molecular Theory and the derivation of the ideal gas equation PV = nRT. Additionally, focus on Graham’s Law of Diffusion and Dalton’s Law of Partial Pressures for numerical-based questions.
03 15 PM IST - 16 Mar'26
AP Intermediate First Year Chemistry Exam 2026: Short Note on Chemical Bonding – Coordinate Covalent Bond
A coordinate bond (dative bond) is formed when one atom provides both electrons for the shared pair, as seen in the formation of NH_4+ or H_3O+. This is a frequent 2-mark question; ensure you can show the donor-acceptor relationship using an arrow (\rightarrow).
03 00 PM IST - 16 Mar'26
AP Intermediate Chemistry Exam 2026: Important QnA 5 For Study
Question: What are Fajan’s rules for determining the covalent character of an ionic bond?
Answer: Fajan’s rules state that covalent character increases with a smaller cation size, a larger anion size, and a higher charge on either ion. Additionally, cations with a "pseudo-noble gas" configuration (ns2 np6 nd^{10}) have greater polarizing power than those with a noble gas configuration.02 45 PM IST - 16 Mar'26
Molecular Orbital Theory (MOT)
You must be able to draw the Molecular Orbital (MO) energy level diagrams for homonuclear diatomic molecules like O_2 and N_2. Use these diagrams to calculate the bond order and predict the magnetic behavior (paramagnetic or diamagnetic) of the species.
02 30 PM IST - 16 Mar'26
Short Note on Chemical Bonding – VSEPR Theory
The Valence Shell Electron Pair Repulsion theory predicts the geometry of molecules based on the idea that electron pairs around a central atom stay as far apart as possible. You must remember the order of repulsion: lp-lp > lp-bp > bp-bp, which explains why NH_3 and H_2O have smaller angles than the ideal tetrahedral angle.
02 15 PM IST - 16 Mar'26
Important QnA 4 For Study
Question: Explain the hybridization involved in the CH_4 molecule.
Answer: In methane, the central carbon atom undergoes sp3 hybridization by mixing one 2s and three 2p orbitals to form four equivalent hybrid orbitals. These orbitals overlap with the 1s orbitals of four hydrogen atoms to create a tetrahedral geometry with a bond angle of 109.5°.02 00 PM IST - 16 Mar'26
AP Inter 1st Year Chemistry Exam 2026: Hybridization in Chemical Bonding
Master the hybridization of central atoms in molecules like CH_4, NH_3,and H_2O to explain their geometry and bond angles. With the increased marks, the sp3d and sp3d2 hybridization in PCl_5 and SF_6 are also likely to appear in Section B.
01 45 PM IST - 16 Mar'26
AP Intermediate First Year Chemistry Exam 2026: Short Note on Periodicity – Ionization Enthalpy Factors
Ionization Enthalpy is influenced by atomic size, nuclear charge, screening effect, and the stability of half-filled or full-filled subshells. In the 2026 exam, expect questions on why noble gases have the highest values and why there are exceptions in Group 15 and 16.
01 30 PM IST - 16 Mar'26
AP Intermediate Chemistry Exam 2026: Important QnA 3 For Study
Question: Why is the first ionization enthalpy of Nitrogen higher than that of Oxygen?
Answer: Nitrogen has a stable, exactly half-filled electronic configuration (1s2 2s2 2p3), which requires more energy to remove an electron. Oxygen, despite having a higher nuclear charge, has a less stable configuration (2p4) and experiences electron-electron repulsion, making it easier to remove the fourth p-electron.01 15 PM IST - 16 Mar'26
Periodic Trends in Elemental Properties
Understanding the variation of Ionization Enthalpy, Electron Gain Enthalpy, and Electronegativity across a period and down a group is crucial for the new 85-mark blueprint. You should pay special attention to "exceptional" trends, such as why Nitrogen has a higher ionization enthalpy than Oxygen.
01 00 PM IST - 16 Mar'26
Short Note on Atomic Structure – Heisenberg’s Uncertainty Principle
This principle states that it is impossible to determine both the exact position and the exact momentum of a subatomic particle like an electron simultaneously. Mathematically expressed as \Delta x \cdot \Delta p \ge \frac{h}{4\pi}, it led to the replacement of the concept of "orbits" with "orbitals."
12 45 PM IST - 16 Mar'26
Important QnA 2 For Study
Question: State the main postulates of Bohr’s model of the hydrogen atom.
Answer: Bohr proposed that electrons revolve around the nucleus in fixed circular paths called stationary orbits without radiating energy. Energy is emitted or absorbed only when an electron jumps from one orbit to another, and the angular momentum of an electron is quantized (mvr = nh/2\pi).12 30 PM IST - 16 Mar'26
AP Inter 1st Year Chemistry Exam 2026: Bohr’s Model and Hydrogen Spectrum
The postulates of Bohr's atomic model and the derivation of the energy of an electron are frequent long-answer candidates. Ensure you can sketch and label the various series in the hydrogen spectrum, specifically the Lyman, Balmer, and Paschen series.
12 15 PM IST - 16 Mar'26
AP Intermediate First Year Chemistry Exam 2026: Short Note on Atomic Structure – Quantum Numbers
Quantum numbers are the "address" of an electron, where the Principal (n) determines size, Azimuthal (l) determines shape, Magnetic (m) determines orientation, and Spin (s) determines the direction of rotation. Understanding the rules like (n+l) is vital for writing correct electronic configurations for transition elements.
12 00 PM IST - 16 Mar'26
Important QnA 1 For Study
Question: Define Quantum Numbers and explain the significance of the Principal Quantum Number (n).
Answer: Quantum numbers are a set of four values used to describe the position and energy of an electron in an atom. The Principal Quantum Number (n) defines the main energy shell and determines the size of the orbital, where the maximum number of electrons in a shell is given by 2n2.
11 45 AM IST - 16 Mar'26
AP Inter 1st Year Chemistry Exam 2026: Quantum Mechanical Model of the Atom
Focus heavily on the significance of the four quantum numbers (n, l, m, s) as they are fundamental for predicting electron configurations. You must also be able to explain the Pauli Exclusion Principle and Hund’s Rule of maximum multiplicity with relevant examples.
