Partition Chromatography:
Paper chromatography (PC) is an example of partition chromatography. The same procedure is followed as in thin layer chromatography except that a strip of paper acts as an adsorbent is method involves continues differential portioning of  components of a mixture between stationary and mobile phase. In paper chromatography, a special quality paper known as chromatography paper is used. This paper act as a stationary phase.
A strip of chromatographic paper spotted at the base with the solution of the mixture is suspended in a suitable solvent which act as the mobile phase solvent rises up and flows over the spot. The paper selectively retains different components according to their different partition in the two phases where a chromatogram is developed. The spots of the separated colored compounds are visible at different heights from the position of initial spots on the chromatogram. The spots of the separated colorless compounds may be observed either under ultraviolent light or by the use of an appropriate spray reagent.

A known mass of the organic compound is heated with fuming HNO₃ and AgNO₃. C, H & S get oxidized to CO₂, H₂O & SO₂ and halogen combines with AgNO₃ to form a precipitate of silver halide.
\(X=\xrightarrow [ fum.HNO_{ 3 } ]{ AgNO_{ 3 } } AgX\downarrow \)
The precipitate of AgX is filtered, washed, dried and weighed. From the mass of AgX and the mass of the organic compound taken, percentage of halogens are calculated.
A known mass of the substance istaken along with fuming HNO₃ and AgNO, is taken in a clean carius tube. The open end of the Carius tube is sealed and placed in a irbn tube for 5 hours in the range at 530- 540 k Then the tube is allowed to cool and a small hole is made in the tube to allow gases produced to escape. The tube is broken and the ppt is filtered, washed, dried and weighed. From the mass of AgX obtained, percentage of halogen in the organic compound is calculated.
Weight of the organic compound : w g
Weight of AgCI precipitate = a g
Percentage of CI in w g = \(\left(\frac{35.5}{143.5} \times \frac{\mathrm{a}}{\mathrm{w}} \times 100\right) \%\)
organic compound
Let Weight of silver Bromide be 'b'g
Percentage of Br in w g = \(\left(\frac{80}{188} \times \frac{b}{w} \times 100\right) \%\) organic compound
Let Weight of silver Iodide be 'c'g
w g Organic compound gives c g AgI
Percentage of l in w g = \(\left(\frac{127}{235} \times \frac{c}{w} \times 100\right) \%\) organic compound.

Homologous series: A series of organic compounds each containing a characteric functional group and the successive' members differ from each other in molecular formula by a CH₂ group is called homologous series. Eg.
Alkanes : Methane (CH₄), Ethane (C₂H₆), Propane (C₃Hg) etc .
Alcohols: Methanol (CH₃OH), Ethanol (C₂H₅OH) Propanol (C₃H₇OH) etc ..)
Compounds of the homologous series are represented by a general formula Alkanes CnH_2n+2' Alkenes C_nH_2n, Alkynes C_nH_2n-2 and can be prepared by general methods. They show regular gradation in physical properties but have almost similar chemical property.

Aliphatic monohydric alcohol : R - OH