Explanation: MgO has the highest lattice energy due to the small ionic radii and high charges (+2 and -2) of Mg2+ and O2-, resulting in very strong electrostatic attractions.
Explanation: In Fe2O3: 2(Fe) + 3(-2) = 0, so 2Fe = 6, Fe = +3.
A Ethane
B Ethene
C Ethyne
D Butane
Explanation: Ethyne (acetylene, C2H2) contains a carbon-carbon triple bond (C≡C), making it an alkyne.
A Reducing agent
B Oxidizing agent
C Catalyst
D Dehydrating agent
Explanation: MnO2 oxidizes HCl to produce Cl2: MnO2 + 4HCl -> MnCl2 + Cl2 + 2H2O. Here MnO2 is the oxidizing agent.
A Propanal
B Propan-2-one
C Propanoic acid
D Propan-1-ol
Explanation: Propanone has the structure CH3COCH3. The carbonyl group is at carbon 2, so its IUPAC name is propan-2-one (commonly called acetone).
Explanation: Primary alkyl halides favor SN2 because they have minimal steric hindrance, and strong nucleophiles with polar aprotic solvents further promote bimolecular substitution.
A Cell potential increases
B Cell potential decreases
C Cell potential remains unchanged
D Cell potential becomes zero
Explanation: As Q increases, the logarithmic term (RT/nF)lnQ becomes more positive, which reduces E from E0, decreasing the cell potential.
A +200 J
B -200 J
C 0 J
D +100 J
Explanation: At constant pressure, q = Delta H. Since heat is released (exothermic), Delta H = -200 J by sign convention.
Explanation: Rate = k[A]^n. If 2^n = 4, then n = 2, meaning the reaction is second order with respect to A.
Explanation: CN- is a strong field ligand at the top of the spectrochemical series, causing the largest crystal field splitting (Delta_o).
A Complete retention of configuration
B Complete inversion of configuration
C Racemization with some inversion
D Complete retention only
Explanation: SN1 proceeds through a planar carbocation intermediate. Nucleophilic attack from both faces gives racemization, but ion pairing often causes slight excess inversion.
A Rate = k[CH3Br]
B Rate = k[OH-]
C Rate = k[CH3Br][OH-]
D Rate = k[CH3Br]^2[OH-]
Explanation: SN2 is bimolecular: both the substrate and nucleophile are involved in the rate-determining step, so Rate = k[CH3Br][OH-].
A 6, +2
B 6, +3
C 3, +3
D 6, +6
Explanation: Six NH3 ligands give coordination number 6. Each NH3 is neutral and 3 Cl- balance the charge, so Co is +3.
A Linkage isomerism
B Geometric (cis-trans) isomerism
C Ionization isomerism
D Coordination isomerism
Explanation: The complex can exist as cis (Cl ligands adjacent) and trans (Cl ligands opposite) geometric isomers due to its octahedral geometry.
A Energy is conserved in all chemical reactions
B The total enthalpy change is independent of the path taken between initial and final states
C All exothermic reactions have negative activation energy
D Equilibrium constant depends on temperature only
Explanation: Hess\'s law states that the total enthalpy change for a reaction is the same regardless of whether it occurs in one step or multiple steps, because enthalpy is a state function.
A They must be gauche
B They must be anti-periplanar (180 degrees dihedral angle)
C They must be syn-periplanar (0 degrees dihedral angle)
D There is no geometric requirement
Explanation: E2 requires an anti-periplanar arrangement where the C-H and C-LG bonds are at 180 degrees, allowing maximum orbital overlap for the developing pi bond.
A Maximum
B Equal to E0
C Zero
D Negative
Explanation: At equilibrium, Q = K and Delta G = 0, so from Delta G = -nFE, we get E = 0. The cell has no driving force at equilibrium.
A NMR spectroscopy
B UV-Vis spectroscopy
C IR spectroscopy
D Mass spectrometry
Explanation: IR spectroscopy measures the absorption of infrared radiation by molecular vibrations (stretching and bending of bonds), revealing functional groups and molecular framework.
A Number of equivalent protons
B The electronic environment of the proton
C The number of neighboring protons
D The molecular weight
Explanation: Chemical shift reflects the shielding/deshielding of a proton by surrounding electrons. Deshielded protons (near electronegative atoms) appear at higher delta values.
A First order
B Second order
C Third order
D Zero order
Explanation: E1 is unimolecular: only the substrate is involved in the rate-determining step (carbocation formation), so Rate = k[substrate], making it first order.