Lecture 6

Question 1

How is intensity related to absorbance

Answer 1

.By Beer lambert law
.Absorbance=ecl

A= absorbance
E=molar absorption coefficient (dm3mol-1cm-1)
C=concentration of solution mol dm-3
l=path length (cm)

Question 2

What is molar absorption coefficient

Answer 2

.probability of transition occurring-selection rules
.larger e more intense the colour

Question 3

What are the selection rules

Answer 3

Laporte rule- orbital quantum number must change by +1or -1 (s-p or p-d)
.parity selection rules-g-g and u-u transitions forbidden but g-u transitions allowed
. Spin selection rule- spin of electron can’t change during electronic transition

Question 4

What are paramagnetic and diamagnetic

Answer 4

.Paramagnetic-contains unpaired electrons (attracted to magnetic field)
.Diamagnetic where all electrons are paired(repelled by magnetic field)
.Diamagnetism weaker than paramagnetism

Question 5

How to measure whether paramagnetic or diamagnetic

Answer 5

.Weigh complex in presence and absence of magnetic field(guoy balance)
.Paramagnetic (weighs more as attracted )
.Diamagnetic weighs less as repelled
.

Question 6

How to determine between square planar and tetrehedral complexes

Answer 6

.Using magnetic moments
.important for first row d8 transition metal complexes
.Electronic preference square planar but steric preferences tetrehedral

Question 7

Example of tetrehedral shape vs square planar

Answer 7

(NiCl4)2- is tetrahedral but (PdCl4)2- is square planar