The first six members of nitro alkanes are
(i) CH₂-NO₂ - Nitromethane
(ii) CH₂-CH₂-NO₂ - Nitroethane
(iii) CH₃-CH₂-CH₂-NO₂ - 1- nitropropane'
(iv) CH₃-CH₂-CH₂-CH₂-NO₂ - 1- nitrobutane
(v) CH₃-CH₂-CH₂-CH₂-CH₂-NO₂ - 1- nitropentane
(vi) CH₂-CH₂-CH₂-CH₂-CH₂-CH₂ - NO₂ - 1- nitrohexane

They are covalent compounds of carbon and generally insoluble in water and readily soluble in organic solvent such as benzene, toluene, ether, chloroform etc...
Many of the organic compounds are inflammable (except CCI₄). They possess low boiling and melting points due to their covalent nature
Organic compounds are characterised by functional groups. A functional group is an atom or a specific combination of bonded atoms that react in a characteristic way, irrespective of the organic molecule in which it is present. In almost all the cases, the reaction of an organic compound takes place at the functional group. They exhibit isomerism which is a unique phenomenon.
Homologous series: Aseries 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(C₃H₈) etc.Alcohols: Methanol (CH₃OH), Ethanol (C₂H₅OH) Propanol (C₃H₇OH) etc..) Compounds of the homologous series are represented by a general formula Alkanes C_nH_2n+2, Alkenes C_nH_2n, Alkynes C_nHr_2n-2 and can be prepared by general methods. They show regular gradation in physicial properties but have almost similar chemical property.

(w) = 0.33 g
(c) = 0.397 g
\(\% I=\frac{127}{235} \times \frac{c}{w} \times 100=\frac{127}{235} \times \frac{0.235}{0.40} \times 100=31.75 \%\)

(w) = 0.185 g
(x) = 0.320 g
\(\% \mathrm{Br}=\frac{80}{188} \times \frac{b}{w} \times 100=\frac{80}{188} \times \frac{0.320}{0.185} \times 100=73.6 \%\)

i) Butan.- I - ol & Butan - 2 -ol are position isomers. - Position isomerism
ii) Butan -I -ol & 2-methyl propan - I - ol are chain isomers - Chainisomerism
iii) Butan -I - ol and I - methoxy propane are functional isomers - Functional isomerism
iv) 1 - methoxy Propane and ethoxy ethane and 2 - methoxy Propane are metamers - Metamerism

A small piece of Na dried by pressing between the folds of a filter Paper is taken in a fusion tube and it is gently heated.
When it melts to a shining globule, put a pinch of the organic compound on it. Heat the tube till reaction ceases and becomes red hot. Plunge it in about 50 mL of distilled water taken in a china dish and break the bottom of the tube by striking against the dish. Boil the contents of the dish for about 10 mts and filter. This filtrate is known as lassaignes extract or sodium fusion extract and it used for detection of nitrogen, sulfur and halogens present in organic compounds.
If nitrogen is present it gets converted to sodium cyanide which reacts with freshly prepared furro,sulphate and feiric ion followed by conc. HCI and gives a Prussian blue color or green color precipitate. It confirms the presence of nitrogen. HCI is added to dissolve the lreenish precipitate of ferrous hydrbxide iroduced by the excess of NaOH on Feson which would otherwise markthe Prussian blue piecipitate. The following reaction takes part in the formation of Prussian blue.


from organic compounds
\(FeSo_{ 4 }+2NaOH\longrightarrow Fe(OH)_{ 2 }+Na_{ 2 }{ SO }_{ 4 }\)
from organic compounds
\(6FeCN+Fe(OH)_{ 2 }\longrightarrow Na_{ 4 }[Fe(CN)]_{ 6 }+2NaOH\)
Sod.ferrocyanide
\(3Na_{ 4 }[Fe(CN)_{ 6 }]+FeC1_{ 3 }\longrightarrow Fe_{ 4 }[Fe(CN)]_{ 3 }+12NaCI\)
ferric ferrocyanidePrussian blue or greenppt
Incase if both N & S are present, a blood red color is obtained due to the following reactions.
\(\mathrm{Na}+\mathrm{C}+\mathrm{N}+\mathrm{S} \stackrel{\text { Heat }}{\longrightarrow} \mathrm{NaCNS}\)
sodium sulphocyanide
\(3 \mathrm{NaCNS}+\mathrm{FeCl}_3 \longrightarrow \mathrm{Fe}(\mathrm{CNS})_3+3 \mathrm{NaCl}\)
ferric sulphocyanide
(Blood red colour).

(w) = 0.33 g
y = 0.397 g
\(\% \mathrm{P}=\frac{62}{222} \times \frac{\mathrm{y}}{\mathrm{w}} \times 100=\frac{62}{222} \times \frac{0.397}{0.33} \times 100=33.60 \%\)

Weight of organic compound = 0.26g
Weight of water = 0.039g
Weight of CO₂ = 0.245g
Percentage of hydrogen
\( \% =\frac{2}{18} \times \frac{x}{\mathrm{w}} \times 100 \)
\(=\frac{2}{18} \times \frac{0.039}{0.26} \times 100 \)
\(=1.66 \%\)
Percentage of carbon
\(\% \mathrm{C} =\frac{12}{44} \times \frac{\mathrm{y}}{\mathrm{w}} \times 100 \)
\(=\frac{12}{44} \times \frac{0.245}{0.26} \times 100=25.69 \% \)