Explanation

• A 3-center 2-electron (3c–2e) bond involves three atoms sharing two electrons.
• This type of bonding occurs in electron-deficient compounds.
• Diborane (B₂H₆) is a famous example of such bonding.
• It contains two bridging hydrogen atoms between boron atoms.
• These bridges form banana-shaped 3c–2e bonds.

Last verified on 19-05-2026

Explanation

• Ionization energy is energy required to remove an electron from an atom.
• Nitrogen has configuration: 1s² 2s² 2p³ (half-filled, stable).
• Oxygen has configuration: 1s² 2s² 2p⁴.
• In oxygen, one p orbital has paired electrons, causing repulsion.
• This repulsion makes electron removal easier in oxygen than nitrogen.

Last verified on 19-05-2026

Explanation

For spontaneity, use Gibbs free energy:

ΔG = ΔH - TΔS

Reaction becomes non-spontaneous when ΔG > 0.  

At the cutoff point ΔG = 0, so:

0 = ΔH - TΔS

T = ΔH / ΔS

Plug in the values. Convert ΔH to J/mol to match units:

ΔH = −40 kJ mol⁻¹ = −40000 J mol⁻¹  

ΔS = −100 J mol⁻¹ K⁻¹

T = (−40000) / (−100) = 400 K

Last verified on 19-05-2026

Explanation

• Dilution means adding more solvent (water) to a solution.
• Molar concentration depends on amount of solute per volume.
• When volume increases, molarity decreases.
• Specific conductivity depends on number of ions per unit volume.
• So both concentration and conductivity decrease on dilution.

Last verified on 19-05-2026

Explanation

• Nernst equation relates electrode potential to reaction conditions.
• It shows how potential changes away from standard conditions.
• Electrode potential depends on ion concentration (or activity).
• It also depends on temperature (T).
• So both factors influence the value of E.

Last verified on 19-05-2026

Explanation

• Bond order is calculated using Molecular Orbital Theory.
• Formula: Bond order = (Bonding electrons − Antibonding electrons) / 2
• O₂ has bond order = 2.
• O₂⁺ means one electron is removed from antibonding orbital.
• Removing antibonding electron increases bond order by 0.5.
• So, bond order of O₂⁺ = 2.5.

Last verified on 19-05-2026

Explanation

• Spontaneity of a reaction is decided by Gibbs free energy (ΔG).
• At constant temperature and pressure, ΔG is the key factor.
• A reaction proceeds on its own when energy is released.
• This means the system moves to a lower energy state.
• So, Gibbs free energy must be negative.

Last verified on 19-05-2026

Explanation

• Nucleophilic acyl substitution occurs in acid derivatives like acyl chlorides.
• Ethanoyl chloride reacts by replacing the halogen atom.
• The carbonyl carbon is attacked by a nucleophile.
• The group that leaves must be stable after departure.
• Chloride ion (Cl⁻) is a good leaving group due to its stability.

Last verified on 19-05-2026

Explanation

• Markovnikov’s rule explains addition of HX to unsymmetrical alkenes.
• Hydrogen (H) attaches to the carbon with more hydrogens already.
• Bromine (Br) attaches to the more substituted carbon.
• Propene (CH₃–CH=CH₂) follows this rule during addition of HBr.
• This forms a more stable secondary carbocation intermediate.

Last verified on 19-05-2026

Explanation

• Critical temperature is a key concept in gas liquefaction.
• It is the highest temperature at which a gas can be liquefied.
• Above this temperature, gas particles have too much kinetic energy.
• No amount of pressure alone can bring molecules close enough to liquefy.
• So liquefaction becomes impossible above this point.

Last verified on 19-05-2026