#neet
- Match List I with List II.List I (Complex): A. [Co(NH_3)_5(NO_2)]Cl_2 B. [Co(NH_3)_5(SO_4)]Br C. [Co(NH_3)_6][Cr(CN)_6] D. [Co(H_2O)_6]Cl_3List II (Type of isomerism): I. Solvate isomerism II. Linkage isomerism III. Ionization isomerism IV. Coordinat… Answer: 2. A-II, B-III, C-IV, D-I Key idea: match each complex to the isomerism it can show. A, [Co(NH₃)₅(NO₂)]Cl₂ : NO₂^- is ambidentate, s... 1
- Given below are two statements:Statement I : The boiling point of hydrides of Group 16 elements follow the orderH_2O > H_2Te > H_2Se > H_2S.Statement II : On the basis of molecular mass, H_2O is expected to have lower boiling point than the other mem… Answer: 2. Both Statement I and Statement II are true. Key idea: boiling point of hydrides depends on H-bonding and on molecular mass. H₂O i... 1
- A compound with a molecular formula of C_6H_14 has two tertiary carbons. Its IUPAC name is: Answer: 4. 2,3-dimethylbutane Key idea: a tertiary carbon is bonded to three other carbons (one C-H). 2,2-dimethylbutane: one quaternary C,... 1
- Match List I with List II.List I (Conversion): A. 1 mol of H_2O to O_2 B. 1 mol of MnO_4^- to Mn^2+ C. 1.5 mol of Ca from molten CaCl_2 D. 1 mol of FeO to Fe_2O_3List II (Number of Faraday required): I. 3F II. 2F III. 1F IV. 5FChoose the correct answ… Answer: 2. A-II, B-IV, C-I, D-III Key idea: Faradays = moles of electrons transferred. A: 2H₂O→ O₂+4H^++4e^- , so 1 mol H₂O needs 2 F (II).... 1
- The compound that will undergo S_N1 reaction with the fastest rate is Answer: 1. [structure: 1-bromoethylbenzene (phenyl-CH(CH ₃ )-Br), see figure] Key idea: S_N1 rate depends on carbocation stability. 1-Bromoe... 1
- Arrange the following elements in increasing order of electronegativity:N, O, F, C, SiChoose the correct answer from the options given below: Answer: 2. Si < C < N < O < F Key idea: electronegativity increases across a period and decreases down a group. Pauling values: Si 1.8 < C 2... 1
- Major products A and B formed in the following reaction sequence, are[scheme: 2-methylcyclohexanol (OH and H_3C on adjacent ring carbons) PBr_3 A (major) [Δ]alc.\ KOH B (major), see figure] Answer: 2. A = [structure: 1-bromo-2-methylcyclohexane], B = [structure: 1-methylcyclohexene (double bond adjacent to methyl carbon)] Key id... 1
- A small telescope has an objective of focal length 140 cm and an eye piece of focal length 5.0 cm. The magnifying power of telescope for viewing a distant object is: Answer: 3. 28 Key idea: For a telescope in normal adjustment (distant object), m=f_o/f_e . m=140/5.0=28 . Option 3. 1
- If the plates of a parallel plate capacitor connected to a battery are moved close to each other, thenA. the charge stored in it, increases.B. the energy stored in it, decreases.C. its capacitance increases.D. the ratio of charge to its potential rem… Answer: 3. A, C and E only Key idea: The capacitor stays connected to the battery, so the voltage V stays fixed. Moving the plates closer re... 1
- A 10 μ F capacitor is connected to a 210 V, 50 Hz source as shown in figure. The peak current in the circuit is nearly (π=3.14): Answer: 3. 0.93 A Key idea: For a capacitor in an AC circuit the capacitive reactance is X_C=1/ω C and the peak current is I₀=V₀/X_C=V₀ω C ,... 1
- Choose the correct circuit which can achieve the bridge balance. Answer: 2. circuit (2) Key idea: A Wheatstone bridge is balanced when no current flows through G, i.e. P/Q=R/S . The top arms are 10 Ω and 1... 1
- Two heaters A and B have power rating of 1 kW and 2 kW, respectively. Those two are first connected in series and then in parallel to a fixed power source. The ratio of power outputs for these two cases is: Answer: 3. 2 : 9 Key idea: P=V²/R , so R∝1/P at fixed voltage. Take R_A=2 units (1 kW) and R_B=1 unit (2 kW). Series: R_s=3 , so P_s=V²/3 .... 1
- The velocity (v) - time (t) plot of the motion of a body is shown below :The acceleration (a) - time (t) graph that best suits this motion is : Answer: 4. graph (4) Key idea: Acceleration is the slope of the v - t graph. Initially v=0 and flat: a=0 . Straight rise: constant positive... 1
- If the mass of the bob in a simple pendulum is increased to thrice its original mass and its length is made half its original length, then the new time period of oscillation is x/2 times its original time period. Then the value of x is: Answer: 3. sqrt2 Key idea: T=2π√(L/g) does not depend on the mass of the bob. Only the length changes: T'=2π√(L/2/g)=T/sqrt2 . Setting T/sqr... 1
- A metallic bar of Young's modulus, 0.5×10^11 N m^-2 and coefficient of linear thermal expansion 10^-5 ^°C^-1, length 1 m and area of cross-section 10^-3 m^2 is heated from 0^°C to 100^°C without expansion or bending. The compressive force developed i… Answer: 3. 50×10³ N Key idea: If the bar is not allowed to expand, the thermal strain αΔ T is cancelled by a compressive strain, so a stress... 1
- A sheet is placed on a horizontal surface in front of a strong magnetic pole. A force is needed to :A. hold the sheet there if it is magnetic.B. hold the sheet there if it is non-magnetic.C. move the sheet away from the pole with uniform velocity if… Answer: 3. A and C only Key idea: A force is needed only if the magnetic pole exerts a force on the sheet. A: A magnetic sheet is attracted... 1
- The property which is not of an electromagnetic wave travelling in free space is that : Answer: 1. they originate from charges moving with uniform speed. Key idea: Electromagnetic waves are produced by accelerated (oscillating)... 1
- A parallel plate capacitor is charged by connecting it to a battery through a resistor. If I is the current in the circuit, then in the gap between the plates : Answer: 3. displacement current of magnitude equal to I flows in the same direction as I. Key idea: Maxwell's displacement current I_d=ε₀dΦ_... 1
- An iron bar of length L has magnetic moment M. It is bent at the middle of its length such that the two arms make an angle 60^° with each other. The magnetic moment of this new magnet is: Answer: 3. M/2 Key idea: Magnetic moment = pole strength × distance between the poles. Bending changes this distance, not the pole strength.... 1
- The minimum energy required to launch a satellite of mass m from the surface of earth of mass M and radius R in a circular orbit at an altitude of 2R from the surface of the earth is: Answer: 2. 5GmM/6R Key idea: The minimum energy is the difference between the total energy in the orbit and the total energy at the surface.... 1
- The following graph represents the T-V curves of an ideal gas (where T is the temperature and V the volume) at three pressures P_1, P_2 and P_3 compared with those of Charles's law represented as dotted lines.Then the correct relation is: Answer: 1. P₁>P₂>P₃ Key idea: For an ideal gas PV=nRT , so at fixed pressure T=P/nRV : the T-V line has slope P/nR . A larger pressure gives... 1
- A force defined by F=α t^2+β t acts on a particle at a given time t. The factor which is dimensionless, if α and β are constants, is: Answer: 3. α t/β Key idea: Every term in a physical formula has the same dimensions as F , so α t² and β t have the dimensions of force. Equ... 1
- Given below are two statements:Statement I : Aniline does not undergo Friedel-Crafts alkylation reaction.Statement II : Aniline cannot be prepared through Gabriel synthesis.In the light of the above statements, choose the correct answer from the opti… Answer: 2. Both Statement I and Statement II are true. Key idea: the -NH₂ group of aniline is basic and reacts with Lewis acids; Gabriel syn... 1
- Match List I with List II.List I (Compound): A. NH_3 B. BrF_5 C. XeF_4 D. SF_6List II (Shape/geometry): I. Trigonal Pyramidal II. Square Planar III. Octahedral IV. Square PyramidalChoose the correct answer from the options given below: Answer: 2. A-I, B-IV, C-II, D-III Key idea: use VSEPR to get the shape of each molecule. NH₃ : 3 bond pairs + 1 lone pair gives trigonal pyr... 1