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Mole Concept - JEE Main 2026 PYQ

StudyBeacon Quiz – Mole Concept (JEE Main 2026 PYQ) Score: 0 Q1.  In the reaction: $2Al + 6HCl \rightarrow 2Al^{3+} + 6Cl^- + 3H_2$ 6.72 L H₂ at STP per mole Al 33.6 L H₂ regardless of T,P 12 L HCl consumed for 6 L H₂ 11.2 L H₂ at STP per mole HCl Check Answer From equation: $6$ mol HCl → $3$ mol H₂ $1$ mol HCl → $\frac{1}{2}$ mol H₂ At STP: $1$ mol gas = 22.4 L $\frac{1}{2} \times 22.4 = 11.2$ L Q2. Reaction: $CaCO_3 + 2HCl → CaCl_2 + H_2O + CO_2$ Given: 90 g $CaCO_3$, 300 mL HCl (38.55%, density 1.13 g/mL) 32.85 g CaCO₃ remains 97.30 g HCl reacted 64.97 g HCl remains 60.32 g HCl remains Check Answer Mass of solution = $300×1.13=339$ g Mass HCl = $0.3855×339=130.7$ g Moles HCl = $\frac{130.7}{36.5}=3.58$ mol Moles CaCO₃ = $\frac{90}{100}=0.9$ mol Needed HCl = $2×0.9=1.8$ mol Excess HCl remains → 64.97 g Q3. $A + 2B → AB_2$ 36 g A (60 g/mol), 56 g B (80 g/mol) A and B only C and D only B and D only A and C only ...
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Modern Physics – JEE Main PYQs (2026) session 1

Modern Physics – JEE Main PYQs (2026) Quiz Important Constants: $h = 6.63 \times 10^{-34}\ \text{J·s}$ $c = 3 \times 10^8\ \text{m/s}$ $e = 1.6 \times 10^{-19}\ \text{C}$ $k = 1.38 \times 10^{-23}\ \text{J/K}$ $1\text{ eV} = 1.6 \times 10^{-19}\ \text{J}$ Score: 0 Q1. Two electrons are moving in orbits of two hydrogen-like atoms with speeds $3 \times 10^5$ m/s and $2.5 \times 10^5$ m/s respectively. If the radii of these orbits are nearly same then the possible order of energy states are respectively: 9 and 8 8 and 10 10 and 12 6 and 5 Check Answer For hydrogen-like atom: $v \propto \frac{1}{n}$ $\frac{v_1}{v_2} = \frac{n_2}{n_1}$ $\frac{3}{2.5} = 1.2$ Closest integer ratio → 9 and 8. Q2. Number of photons of equal energy emitted per second by a 6 mW laser source operating at 663 nm is: $1\times10^{16}$ $5\times10^{16}$ $2\times10^{16}$ $5\times10^{15}$ Check Answer $E = \frac{hc}{\lambda}$ $E = \frac{6.63\times10^{-34...
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Class 12 Chemistry – 50 most repeated MCQ Test

🧪 Class 12 Chemistry – Full 50 MCQ Test (30 Minutes) Time Left: 30:00 Q1. Number of atoms in BCC unit cell? 1 2 3 4 Q2. Highest melting solid? Ionic Molecular Metallic Covalent network Q3. Schottky defect decreases density? True False Q4. Coordination number of FCC? 4 6 8 12 Q5. Packing efficiency of BCC? 52% 68% 74% 84% Q6. Unit of molality? mol/L mol/kg g/L g/kg Q7. Law relating vapour pressure and mole fraction? Henry’s Law Raoult’s Law Dalton’s Law Ostwald’s Law Q8. Van’t Hoff factor of NaCl? 1 2 3 4 Q9. Colligative properties depend on? Nature of solute Nature of solvent Number of solute particles Temperature only Q10. Osmosis occurs through? Metal sheet Porous membrane Semi-permeable membrane Rubber membrane Q11. Unit of molar conductivity? S cm² mol⁻¹ S cm⁻¹ Ω cm Ω⁻¹ Q12. Standard potential of SHE? 1 V 0 V –1 V 0.5 V Q13. ...
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Alternating Current (AC) – Complete Formula Framework (JEE Mains)

Alternating Current (AC) – Complete Formula Framework (JEE Mains) Phasors | Impedance | Resonance | Power | PYQ Mapping 1️⃣ AC Basics Alternating current: \[ i = I_0 \sin \omega t \] Peak current = \( I_0 \) Angular frequency = \( \omega = 2\pi f \) Time period = \( T = \frac{2\pi}{\omega} \) RMS value: \[ I_{rms} = \frac{I_0}{\sqrt{2}} \] \[ V_{rms} = \frac{V_0}{\sqrt{2}} \] ⚠ Mains Trap: Household voltage is RMS, not peak. 2️⃣ AC through Pure Resistor Voltage & current in phase \[ V = IR \] Power: \[ P = V_{rms} I_{rms} \] Phase angle: \[ \phi = 0 \] 3️⃣ AC through Pure Inductor Inductive reactance: \[ X_L = \omega L \] Current: \[ I = \frac{V}{X_L} \] Phase: \[ \phi = +90^\circ \] Voltage leads current. 4️⃣ AC through Pure Capacitor Capacitive reactance: \[ X_C = \frac{1}{\omega C} \] Current: \[ I = \frac{V}{X_C} \] Phase: \[ \phi = -90^\circ \] Current leads voltage. 5️⃣ RLC Series Circuit Imped...
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