NEET UG

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4d, 5p, 5f and 6p orbitals are arranged in the order of decreasing energy. The correct option is : Answer: 1. 5f > 6p > 5p > 4d Orbital energy in a many-electron atom follows the (n+l) rule; if (n+l) is equal, the orbital with lower n has... Aufbau, Pauli and Hund's rule, electronic configuration, half-filled/filled stability 1 answer
The non-essential amino acid among the following is : Answer: 3. alanine Essential amino acids cannot be made by the body and must come from food: valine, leucine, lysine (and isoleucine, etc.).... Amino acids, peptide bond, protein structure, denaturation 1 answer
Which of the following diatomic molecular species has only π bonds according to Molecular Orbital Theory ? Answer: 3. C ₂ Write the MO configuration for each molecule. C₂ (12 electrons): σ_1s²σ_1s^(*2)σ_2s²σ_2s^(*2)π_2p⁴ . The 2p electrons occupy... Molecular orbital theory, bond order, bond length, bond energy 1 answer
If the rate constant for a first order reaction is k, the time (t) required for the completion of 99% of the reaction is given by : Answer: 3. t = 4.606/k For a first order reaction t = 2.303/klog[A]₀/[A] . When 99% is complete, [A] = 0.01[A]₀ , so t = 2.303/klog 100 = 2.... Integrated rate equations and half-life (zero and first order) 1 answer
Under isothermal condition, a gas at 300 K expands from 0.1 L to 0.25 L against a constant external pressure of 2 bar. The work done by the gas is :[Given that 1 L bar = 100 J] Answer: 4. 30 J Key idea: for expansion against a constant external pressure, the magnitude of work is p_extΔ V , and the question asks for... First law: work, heat, internal energy, enthalpy 1 answer
For the second period elements the correct increasing order of first ionisation enthalpy is : Answer: 2. Li < B < Be < C < O < N < F < Ne First ionisation enthalpy generally increases across a period, with two exceptions in period 2.... Ionization enthalpy and electron gain enthalpy 1 answer
Enzymes that utilize ATP in phosphate transfer require an alkaline earth metal (M) as the cofactor. M is : Answer: 2. Mg ATP-utilising enzymes (phosphate transfer) need mathrmMg²⁺ as cofactor; Mg binds the phosphate groups of ATP. Ca is mainly inv... Valence, oxidation states and chemical reactivity 1 answer
pH of a saturated solution of Ca(OH)_2 is 9. The solubility product (K_sp) of Ca(OH)_2 is : Answer: 1. 0.5×10⁻¹⁵ Use pH to get [OH^-] , then write K_sp . pH = 9 so pOH = 5 and [OH^-] = 10⁻⁵ M. mathrmCa(OH)₂ ⇌ Ca²⁺ + 2OH^- , so [math... Solubility product 1 answer
The most suitable reagent for the following conversion, is :H_3C-C C-CH_3 → cis-2-butene Answer: 2. H ₂ , Pd/C, quinoline Partial reduction of an alkyne to a cis-alkene needs syn addition of H₂ on a poisoned catalyst, i.e. Lindla... Alkynes: acidic character and addition reactions 1 answer
The structure of intermediate A in the following reaction, is :[Reaction: cumene (isopropylbenzene) O_2 A [H_2O]H^+ phenol + acetone] Answer: 2. (2) cumene hydroperoxide: C6H5-C(CH3)2-O-O-H In the cumene process, cumene is oxidised by air at the benzylic tertiary C-H bond t... Phenols: acidity, electrophilic substitution, Reimer-Tiemann 1 answer
Among the following, the one that is not a green house gas is : Answer: 4. sulphur dioxide Greenhouse gases absorb infrared radiation re-emitted by the Earth. N₂O , CH₄ and O₃ (and CO₂ , CFCs) all do. SO₂... Electronic configuration and general trends, Group 13 and 14 1 answer
Which of the following is incorrect statement ? Answer: 1. PbF ₄ is covalent in nature Go through the statements. PbF₄ is ionic (Pb(IV) with the very electronegative F), so the statement '... Electronic configuration and general trends, Group 13 and 14 1 answer
Match the following :(a) Pure nitrogen (i) Chlorine(b) Haber process (ii) Sulphuric acid(c) Contact process (iii) Ammonia(d) Deacon's process (iv) Sodium azide or Barium azideWhich of the following is the correct option ? Answer: 4. (a)-(iv), (b)-(iii), (c)-(ii), (d)-(i) (a) Pure nitrogen: obtained by heating sodium azide or barium azide, (iv). (b) Haber proce... Electronic configuration and general trends, Group 13 and 14 1 answer
Which is the correct thermal stability order for H_2E (E = O, S, Se, Te and Po) ? Answer: 3. H ₂ Po < H ₂ Te < H ₂ Se < H ₂ S < H ₂ O Thermal stability of hydrides of group 16 depends on the E-H bond strength, which falls... General trends, Group 15 and 16 1 answer
The correct structure of tribromooctaoxide is : Answer: 1. (structure 1, see figure) Tribromooctaoxide is the neutral molecule Br₃O₈ with a Br-Br-Br chain. The figure shows the structure w... General trends, Group 17 and 18 1 answer
For the cell reaction2Fe^3+(aq) + 2I^-(aq) → 2Fe^2+(aq) + I_2(aq)E^_cell = 0.24 V at 298 K. The standard Gibbs energy (Δ_rG^) of the cell reaction is :[Given that Faraday constant F = 96500 C mol^-1] Answer: 1. -46.32 kJ mol ⁻¹ Formula: Δ_rG^(ominus) = -nFE^(ominus)_cell . In the reaction 2mathrmFe³⁺ + 2I^- → 2mathrmFe²⁺ + I₂ , 2 electron... Cell potential and Gibbs energy 1 answer
Which of the following reactions are disproportionation reaction ?(a) 2Cu^+ → Cu^2+ + Cu^0(b) 3MnO_4^2- + 4H^+ → 2MnO_4^- + MnO_2 + 2H_2O(c) 2KMnO_4 Δ K_2MnO_4 + MnO_2 + O_2(d) 2MnO_4^- + 3Mn^2+ + 2H_2O → 5MnO_2 + 4H^Select the correct option from th… Answer: 1. (a) and (b) only A disproportionation reaction is one in which the same species is both oxidised and reduced. (a) mathrmCu^+ → Cu... Oxidation and reduction, oxidation number 1 answer
The biodegradable polymer is : Answer: 2. nylon 2-nylon 6 Nylon 2-nylon 6 is a copolymer of glycine and amino caproic acid joined by peptide (amide) linkages that enzymes... Functional groups, homologous series, classification 1 answer
The number of sigma (σ) and pi (π) bonds in pent-2-en-4-yne is : Answer: 1. 10 σ bonds and 3 π bonds Count every bond in pent-2-en-4-yne, CH₃-CH=CH-Cequiv CH . A single bond is one σ ; a double bond is 1 σ... Tetravalency of carbon, hybridization and shapes 1 answer
A 800 turn coil of effective area 0.05 m^2 is kept perpendicular to a magnetic field 5×10^-5 T. When the plane of the coil is rotated by 90^° around any of its coplanar axis in 0.1 s, the emf induced in the coil will be : Answer: 4. 0.02 V The coil starts perpendicular to the field (flux =NBA ) and, after rotating 90^° , lies parallel to it (flux zero). ε=Δφ/Δ... Faraday's law, induced emf and current 1 answer
A parallel plate capacitor of capacitance 20 μF is being charged by a voltage source whose potential is changing at the rate of 3 V/s. The conduction current through the connecting wires, and the displacement current through the plates of the capacit… Answer: 2. 60 μ A, 60 μ A In a charging capacitor the conduction current in the wires equals the displacement current between the plates, so... Displacement current 1 answer
The correct Boolean operation represented by the circuit diagram drawn is : Answer: 3. NAND In the circuit the two switches A and B are in series between the LED node and ground. Taking the switch position 1 as close... Logic gates (OR, AND, NOT, NAND, NOR) 1 answer
A cylindrical conductor of radius R is carrying a constant current. The plot of the magnitude of the magnetic field, B with the distance, d, from the centre of the conductor, is correctly represented by the figure : Answer: 3. [graph] B increasing linearly for d < R, peak at R, then decreasing for d > R By Ampere's law for a cylindrical conductor with un... Ampere's law: straight wire and solenoid 1 answer
The radius of circle, the period of revolution, initial position and sense of revolution are indicated in the fig.y-projection of the radius vector of rotating particle P is : Answer: 4. y(t) = 3cos(π t/2) , where y in m From the figure, A=3 m, T=4 s so ω=2π/T=π/2 rad/s. At t=0 the particle is at the top of the cir... SHM and its equation, phase 1 answer

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