(i) Aldehyde : \(\underset{\\\\ \ -\mathrm{C}-\mathrm{H}}{\overset{\mathrm{O}}{||}}\)
(ii) Alcohol: -OH

Functional group: Ketone, name of the compound: Propanone.

Hydrogenation.

Butanol

 C₂H₆C₃H₆

Soap is alkaline in nature. Hence, it turns red litmus paper blue and have no effect on the blue litmus paper.

Alcohol and carboxylic acid can be distinguished experimentally by two reactions:
(i) Reaction with Base
Alcohols do not react with base like NaOH, KOH while carboxylic acids react with base to form salt and water.
e.g. CH₃COOH + NaOH \(\rightarrow\) CH₃CO\(\bar{O}\)\(\overset{+}{N}\)a + H₂O
CH₃CH₂OH + NaOH \(\rightarrow\) No reaction
(ii) Reaction with Sodium bicarbonate
Carboxylic acids react with sodium bicarbonate rapidly to give brisk effervescence of CO₂ gas while alcohols do not react.
e.g. CH₃COOH + NaHCO₃ \(\rightarrow\) CH₃COONa + H₂O + CO₂\(\uparrow\)
CH₃CH₂OH + NaHCO₃ \(\rightarrow\) No reaction

We need a high temperature for welding but when ethyne is burnt in air, it undergoes incomplete combustion and releases a lot of smoke and the temperature is also not very high. In order to ensure complete oxidation and to obtain the high temperature needed for welding, a mixture of ethyne and oxygen is used.
2CH \(\equiv\) CH + 5O₂ \(\rightarrow\) 4CO₂ + 2H₂O + Heat + Light
 

Two main properties which led the carbon to form a huge. number of carbon compounds are:
(i) catenation
(ii) tetravalency of carbon

A series of similarly constituted compounds in which the members present have the same functional group and similar chemical properties and any two successive members in a particular series differ in their molecular formula by ( - CH₂) unit, is called a homologous series.
e.g. alkane series C_nH_2n+2

Substances that are capable of providing oxygen to other substances are called oxidising agents. Alkaline potassium permanganate (KMnO₄) or acidified potassium dichromate (K₂Cr₂O₇) act as an oxidising agent in oxidising alcohols into acids.

a) When carbon dioxide is passed through the calcium hydroxide solution, it turns milky due to the formation of insoluble calcium carbonate.
b) Reaction in Test tube A:
\(\underset{Acetic\ or\ ethnoic\ acid}{2CH_3COOH(1)}+\underset{Sodium\ carbonate}{Na_2CO_3(s)}\rightarrow\underset{Sodium\ acetate}{2CH_3COONa}+\underset{Water}{H_2O}+\underset{Carbon\ ioxide}{CO_2(g)}\)
Reaction in Test tube B:
\(\underset{Calciumhydroxide\\ (Lime\ water)}{Ca(OH)_2(aq)}+\underset{Carbondioxide}{CO_2(g)}\rightarrow\underset{Calcium\ carbonate\\ (White\ ppt)}{CaCO_3(s)\downarrow}\underset{Water}{H_2O}\)
c) No with ethanol no reaction takes place.
d) When a quick lime i.e., calcium oxide is added to water in a test tube, it forms calcium hydroxide which is lime water. This solution is filtered and the clear solution is obtained
\(CaO(s)+H_2O(l)\rightarrow Ca(OH)_2\)

i) Since compound C on combustion forms two moles of CO₂ and 3 moles of H₂ O, therefore compound C must contain two carbon atoms and six hydrogen atmos. Thus compound C must be C₂H₆ (ethane)
\(\underset{Ethene(C)}{2C_2H_6}+\underset{Oxygen}{7O_2}\xrightarrow{Heat}\underset{Carbon\ dioxide}{4CO_2}+\underset{Water}{6H_2O}\)
ii) Since compound (C) is obtained by addition of 1 mole of H₂ in presence of Ni to compound (B), therefore (B) must be ethane.
\(\underset{Ethene(B)}{CH2}=CH_2+H_2\xrightarrow{Ni/Heat}\underset{Ethene(C)}{CH_3-CH_3}\)
iii) Since compound (B) is formed by heating compound (A) with cone. H₂SO₄ therefore compound (A) must be ethanol.
\(\underset{Ethanol(A)}{CH_3CH_2OH}\xrightarrow{Conc. H_2SO_4,443K}CH_2=CH_2+\underset{Ethene(B)}{H_2O}\)

Carboxylic acid reacts with alcohols to form ester. For example, when ethanoic acid is warmed with ethanol in presence of a few drops of concentrated sulphuric acid as catalyst, an ester (ethyl ethanoate, commonly called ethyl acetate) and water are formed.
\(\underset{Acetic\ or\ ethanoic\ acid}{CH_COOH}+\underset{Ethanol}{C_2H_5OH}\xrightarrow{Conc. H_2SO_4}\underset{Ethyl\ ethanoate}{CH_3COOC_2H_5}+\underset{Water}{H_2O)}\)
Ester are sweet -smelling substances. So they are widely used in making perfumes and flavoring agents. Further, the reaction between a carboxylic acid and an alcohol to form a sweet ester is used as a test for alcohols as well as carboxylic acids.

\(\underset{Carbon}{C}+\underset{Chlorine}{2Cl_2}\xrightarrow{Heat}\underset{Carbon\ tetrachloridse}{CCl_4}\)
Its electron dot structure and structural formulae are:

b) Saponification - Alkaline hydrolysis of an ester to give the salt of the corresponding
acid and the alcohol is called saponification. It is reverse of esterification reaction.
For example.
\(\underset{Ester}{CH_3COOC_2H_5}+\underset{sodium\ hydroxide}{NaOH}\xrightarrow{Heat}\underset{Sodium\ acetate}{CH_3COONa}+\underset{Ethanol}{CH_3CH_2OH}\)
Dehydration means removal of a molecule of water. When ethanol is heated with
conc. H2SO₄ at 443 K, it undergoes dehydration to form ethene.
\(\underset{Ethanol}{CH_3CH_2OH}\xrightarrow{Conc. H_2SO_4,443K}\underset{Ethene}{CH_2=CH_2+H_2O}\)

When soap is at the surface of water, the hydrophobic 'tail' of soap will not be soluble in water and the soap will align along the surface of water with the ionic end in water and the hydrocarbon 'tail' protruding out of water. Inside water, these molecules have a unique orientation that keeps the hydrocarbon portion out of the water. This is achieved by forming clusters of molecules in which the hydrophobic tails are in the interior of the cluster and the ionic ends are on the surface of the cluster. This formation is called micelle.
Micelle will not form in all types of solvents. It will form in such type of solvent in which soap is soluble. e.g. soap is insoluble in ethanol, hence, no micelle formation takes place.