class 11th IPE chem SAQs

Diborane Molecular Formula

B{2}H{6} (An electron deficient molecule)

Structure of Diborane - Groups

Contains 2 coplanar BH_{2} groups

Diborane - Terminal Hydrogens (H_{t})

The 4 hydrogen atoms located at the ends of the molecule

Diborane - Bridge Hydrogens (H_{b})

2 middle hydrogens lying in a plane perpendicular to the BH_{2} groups

Diborane - Boron Hybridisation

sp^{3} hybridisation forming 4 hybrid orbitals

Banana Bond (Tau Bond)

A 3-centered 2-electron (3c-2e) hydrogen bridge between two Boron atoms

Haber's Process Equation

N{2(g)} + 3H{2(g)} \rightleftharpoons 2NH_{3(g)} (\Delta H = -92 kJ)

Haber's Process - Ideal Pressure

200-300 atm (High pressure favours ammonia yield)

Haber's Process - Optimum Temperature

725 K - 775 K

Haber's Process - Catalyst & Promoter

Powdered Iron (Fe) as catalyst and Molybdenum (Mo) as promoter

SF_{6} Hybridisation

sp^{3}d^{2} hybridisation of the central Sulphur atom

SF_{6} Molecular Shape & Angles

Octahedral shape with bond angles of 90^{\circ} and 180^{\circ}

Ionic Compounds - Physical State

Generally crystalline solids

Ionic Compounds - Electrical Conductivity

Conduct electricity in molten state or aqueous solution

Ionic Compounds - Boiling/Melting Points

Possess high B.P. and M.P.

Fajan's Rule - Cation Size

As size of cation increases, ionic nature of the bond increases (Li^{+} < Na^{+} < K^{+} < Rb^{+})

Fajan's Rule - Anion Size

Smaller anion size results in greater ionic nature (e.g., CaF{2} > CaI{2})

Fajan's Rule - Charge

Low charges on cation/anion favour the formation of ionic bonds

Kinetic Theory - Particle Motion

Gaseous molecules move randomly in all directions with different velocities

Kinetic Theory - Collisions

Collisions are perfectly elastic; total energy remains constant

Kinetic Theory - Average K.E.

Directly proportional to the absolute temperature (K.E. \propto T)

Intensive Properties

Properties independent of the amount of substance (e.g., Density, Pressure, Temperature)

Extensive Properties

Properties dependent on the amount of substance (e.g., Mass, Volume, Heat Capacity)

Hydrogen Fuel Advantages

Releases large quantity of heat energy; fewer pollutants than petrol

Utility of Hydrogen

Used as rocket fuel, in fuel cells, and for welding/cutting (atomic H torches)