small important things in inorganic

APPLICATION OF DIPOLE DIPOLE FORCE:

diple- dipole boiling point

Molecule with 0 dipole moment shows minimum boiling point and with maximum boiling point shows maximum boiling point.

ex: Cis isomers have high boiling point than trans.

MELTING POINT SYMMETRY PACKING 1/size

ex: s-block have low Melting point while d-block have high MP

Trans isomers have higher melting point than cis due 2 symmetry

Para isomers have high MP due 2 symmetry.

WHY ICE FLOATS ON WATER?

Ice has tetrahedral arrangement of water in which one H2O moleule is surrounded by 4 other H2O molecules and leave large vacant spaces due to which its volume increases and density decreases.

WHAT ARE ELATHRATES OF CAGE COMPOUNDS?

when noble gases like Ar, Kr, Xe are passed into H2O and suddenly freezed then dese gases get trapped in the vacant spaces of ice. such compounds are called cage-compounds.

ION DIPOLE FORCE:

When ionic compound or polar covalent compound is dissolved in water or polar solvents then

1. cation is surrounded by negative part of the solvent by ion dipole force for Group 1 and Group 2 cations. Coordination No is 6 but 4 Li and Be it is 4.

due to absence of d-orbital

NaCl when hydrated gives [Na(H2O)6]

Anion is surrounded by positive part of the solvent by ion dipole force

Which is:

a)H(delta +ve) if solvent is polar protic (which can donate H) and here the ion dipole force is called as H bonding

b) other dn H if the solvent is polar protic solvent and the ion dipole force is not the H bond

CONCLUSION: solvation energy is more in case of polar protic solvents hence the stability for the formation of cation or anion is more.

Q. Why does Li doesn't form alum?

A. for the formation of alum the required coordination number for the cation is six but Li has coordination number 4.

TO CHECK SOLUBILITY:

1.HYDRATION ENERGY

2. ABILITY TO GET POLARIZED

3.PHYSICAL STATE

find the solubility order of iodine, bromine and Chlorine:

answer: Cl2I2

EXPLANATION: I2 is polarized to a greater extent but due to its large size and its solid state it is less soluble.

Br2 secondly polarizes to a greater extent ( less dn I) and due to itz liquid nature it is more soluble in water.

INSTANTANEOUS DIPOLE INDUCED DIPOLE FORCES:

In non polar gaseous molecules due to collison or friction momentarily dipole is produced which in turn produced the dipole produce the dipole in the neighbouring moleule.

Ex: all noble gases

this force only is called as VANDER WAAL FORCE.

order of Vander waal force:

He

more the vander waal force more easy is the liquification.

Boiling Point: NH3 > PH3

H2O > H2S

HF > HCl <>

such order is due to H-bonding

and the boiling point increases downward due to increase in vanderwaal force of attraction.

Vander Waal force exists in all states of matter.

Liquids/solids in which molecules are held together by weak V.W. forces are volatile/sublime

VOLATILE LIQUIDS ACT AS GOOD FUELS.