Class Science English · Part

CH − CH − CH − OH Step : The locant number of –OH group is and thus the secondary suffix is ‘ -ol’. The name of the compound is Prop + an e + ( -ol) = Propan- -ol Note: Terminal ‘e’ of ‘ane’ is removed as per Rule Example : CH COOH Step1: The parent chain consists of carbon atoms. The root word is ‘Eth’. Step : All are single bonds between the carbon atoms of the chain.

So the primary suffix is ‘ane’. Step : Since the compound contains the–COOH group, it is a carboxylic acid. The secondary suffix is ‘oic acid’ The name of the compound is Eth + an e + oic acid) = Ethanoic acid Table . lists IUPAC names homologs of various classes of organic compounds Test yourself: Obtain the IUPAC name of the following compounds systematically: (a) CH CHO (b) CH CH COCH (c) ClCH -CH -CH -CH Carbon and its Compounds .

ETHANOL (CH CH OH) Ethanol is commonly known as alcohol. All alcoholic beverages and some cough syrups contain ethanol. Its molecular formula is C H OH. Its structural formula is Ethanol H—C—C— O—H H H H H — — — — (C H OH) .

. Manufacture of ethanol Ethanol is manufactured in industries by the fermentation of molasses, which is a by-product obtained during the manufacture of sugar from sugarcane. Molasses is a dark coloured syrupy liquid left after the crystallization of sugar from the concentrated sugarcane juice. Molasses contain about % of sucrose, which cannot be separated by crystallization.

It is converted into ethanol by the following steps: (i) Dilution of molasses Molasses is first diluted with water to bring down the concentration of sugar to about to percent. (ii) Addition of Nitrogen source Molasses usually contains enough nitrogenous matter to act as food for yeast during the fermentation process. If the nitrogen content of the molasses is poor, it may be fortified by the addition of ammonium sulphate or ammonium phosphate . (iii) Addition of Yeast The solution obtained in step (ii) is collected in large ‘fermentation tanks’ and yeast is added to it.

The mixture is kept at about 303K for a few days. During this period, the enzymes invertase and zymase present in yeast, bring about the conversion of sucrose into ethanol. C H O + H O C H O + C H O Sugar invertase fructose glucose C H O 2C H OH + CO glucose or fructose zymase ethanol The fermented liquid is technically called wash . (iv) Distillation of 'Wash' The fermented liquid (i.e.

wash), containing to percent alcohol, is now subjected to fractional distillation. The main fraction drawn is an aqueous solution of ethanol which contains Table . IUPAC Name of various classes of compounds No. of carbons atoms IUPAC Name Alcohols Aldehydes Ketones Carboxylic acid Methanol (CH OH) Methanal (HCHO) Methanoic acid (HCOOH) Ethanol (CH CH OH) Ethanal (CH CHO) Ethanoic acid (CH COOH) Propanol (CH CH CH OH) Propanal (CH CH CHO) Propanone (CH COCH ) Propanoic acid (CH CH COOH) Butanol (CH CH CH CH OH) Butanal (CH CH CH CHO) Butanone (CH COCH CH ) Butanoic acid (CH CH CH COOH) Pentanol (CH CH CH CH CH OH) Pentanal (CH CH CH CH CHO) Pentanone (CH COCH CH CH ) Pentanoic acid (CH CH CH CH COOH) .

% of ethanol and . % of water. This is called rectified spirit . This mixture is then refluxed over quicklime for about to hours and then allowed to stand for hours.

On distillation of this mixture, pure alcohol ( %) is obtained. This is called absolute alcohol . More to know Yeast and Fermentation: Yeasts are single–celled microorganisms, belonging to the class of fungi. The enzymes present in yeasts catalyse many complex organic reactions.

Fermentation is conversion of complex organic molecules into simpler molecules by the action of enzymes. E.g. Curdling of milk . .

Physical properties i) Ethanol is a colourless liquid, having a pleasant smell and a burning taste. ii) It is a volatile liquid. Its boiling point is C (351K), which is much higher than that of its corresponding alkane, i.e. ethane (Boiling Point = K).

iii) It is completely miscible with water in all proportions. . . Chemical Properties (i) Dehydration (Loss of water) When ethanol is heated with con H SO at 443K, it loses a water molecule i.e.

dehydrated to form ethene. CH CH OH CH = CH + H O Ethanol Ethene (ii) Reaction with sodium: Ethanol reacts with sodium metal to form sodium ethoxide and hydrogen gas. 2C H OH + 2Na 2C H ONa + H ↑ sodium ethoxide 443K Conc.H SO (iii) Oxidation: Ethanol is oxidized to ethanoic acid with alkaline KMnO or acidified K Cr O CH CH OH CH COOH +H O [O] Ethanoic acid During this reaction, the orange colour of K Cr O changes to green. Therefore, this reaction can be used for the identification of alcohols.

(iv) Esterification: The reaction of an alcohol with a carboxylic acid gives a compound having fruity odour. This compound is called an ester and the reaction is called esterification. Ethanol reacts with ethanoic acid in the presence of conc. H SO to form ethyl ethanoate, an ester.

C H OH + CH COOH CH COOC H + H O Ethanol Ethanoic acid Ethyl ethanoate conc.H SO (v) Dehydrogenation: When the vapour of ethanol is passed over heated copper, used as a catalyst at K, it is dehydrogenated to acetaldehyde. CH CH OH CH CHO + H Ethanol Acetadehyde Cu 573K (vi) Combustion: Ethanol is highly inflammable liquid. It burns with oxygen to form carbon dioxide and water. C H OH + 3O 2CO + 3H O Ethanol Carbon dioxide .

. Uses of ethanol Ethanol is used in med ical wipes, as an antiseptic. as an anti-freeze in automobile radiators. for effectively killing micro organisms like bacteria, fungi, etc., by including it in many hand sanitizers.

K Cr O / H + Carbon and its Compounds as an antiseptic to sterilize wounds in hospitals. as a solvent for drugs, oils, fats, perfumes, dyes, etc. in the preparation of methylated spirit (mixture of % of ethanol and % of methanol) rectified spirit (mixture of . % of ethanol and .

% of water), power alcohol (mixture of petrol and ethanol) and denatured spirit (ethanol mixed with pyridine). to enhance the flavour of food extracts, for example vanilla extract; a common food flavour, which is made by processing vanilla beans in a solution of ethanol and water. . ETHANOIC ACID (CH COOH) Ethanoic acid or acetic acid is one of the most important members of the carboxylic acid family.

Its molecular formula is C H O . Its structural formula is H — C — C — OH H H — — — — O . . Manufacture of ethanoic acid Ethanoic acid is prepared in large scale, by the oxidation of ethanol in the presence of alkaline potassium permanganate or acidified potassium dichromate.

KMnO / OH - CH CH OH CH COOH + H O Ethanol [O] Ethanoic acid . . Physical Properties (i) Ethanoic acid is a colourless liquid having an unpleasant odour. (ii) It is sour in taste.

(iii) It is miscible with water in all proportions. (iv) Its boiling point is higher than the corresponding alcohols, aldehydes and ketones. (v) On cooling, pure ethanoic acid is frozen to form ice like flakes. They look like glaciers, so it is called glacial acetic acid.

. . Chemical Properties (i) Reaction with metal: Ethanoic acid reacts with active metals like Na, Zn, etc., to liberate hydrogen and form their ethanoate. 2CH COOH + Zn → (CH COO) Zn + H ↑ 2CH COOH + 2Na → 2CH COONa + H ↑ (ii) Reaction with carbonates and bicarbonates: Ethanoic acid reacts with sodium carbonate and sodium bicarbonate, which are weaker bases and liberates CO , with brisk effervescence.

2CH COOH + Na CO → 2CH COONa + CO ↑ + H O CH COOH + NaHCO → CH COONa + CO ↑ + H O (iii) Reaction with base: Ethanoic acid reacts with sodium hydroxide to form sodium ethanoate and water. CH COOH + NaOH → CH COONa + H O (iv) Decarboxylation (Removal of CO ): When a sodium salt of ethanoic acid is heated with soda lime (solid mixure of parts of NaOH and part of CaO), methane gas is formed. NaOH / CaO CH COONa CH ↑ + Na CO . .

Uses of ethanoic acid Acetic acid, in lower concentration, (vinegar) is used as a food additive, a flavoring agent and a preservative. Ethanoic acid is used in the manufacture of plastic. in making dyes, pigments and paint. in printing on fabrics.

as a laboratory reagent. for coagulating rubber from latex. in the production of pharmaceuticals. .

ORGANIC COMPOUNDS IN DAILY LIFE Organic compounds are inseparable in human life. They are used by mankind or associated at all stages of life right from one's birth to death. Various classes of organic compounds and their uses in our daily life as follows: Hydrocarbons Fuels like LPG, Petrol, Kerosene. Raw materials for various important synthetic materials.

Polymeric materials like tyre, plastic containers. Alcohols As a solvent and an antiseptic agent. Raw materials for various important synthetic materials. Aldehydes Formaldehyde as a disinfectant.

Raw materials for synthetic materials. Ketones As a solvent. Stain Remover. Ethers Anaesthetic agents.

Pain Killer. Esters All the cooking oils and lipids contain esters. . SOAPS AND DETERGENTS Soaps and the Detergents are materials that are used by us for cleaning purposes because pure water alone cannot remove all types of dirt or any oily substance from our body or clothes.

They contain ‘surfactants’, which are compounds with molecules that line up around water to break the ‘surface tension’. Both of them having a different chemical nature. Soap is a cleaning agent that is composed of one or more salts of fatty acids. Detergent is a chemical compound or a mixture of chemical compounds, which is used as a cleaning agent, also.

They perform their cleaning actions in certain specific conditions. You will learn more about this in detail, in the following units. . .

Soap Soaps are sodium or potassium salts of some long chain carboxylic acids, called fatty acids. Soap requires two major raw materials: i) fat and ii) alkali. The alkali, most commonly used in the preparation of soap is sodium hydroxide. Potassium hydroxide can also be used.

A potassium-based soap creates a more water- soluble product than a sodium-based soap. Based on these features, there are two types of soaps: A. HARD SOAP Soaps, which are prepared by the saponification of oils or fats with caustic soda (sodium hydroxide), are known as hard soaps. They are usually used for washing purposes.

B. SOFT SOAP Soaps, which are prepared by the saponification of oils or fats with potassium salts , are known as soft soaps. They are used for cleansing the body. Manufacture of soap KETTLE PROCESS: This is the oldest method.

But, it is still widely used in the small scale preparation of Carbon and its Compounds soap. There are mainly, two steps to be followed in this process. i) Saponification of oil: The oil, which is used in this process, is taken in an iron tank (kettle). The alkaline solution ( %) is added into the kettle, a little in excess.

The mixture is boiled by passing steam through it. The oil gets hydrolysed after several hours of boiling. This process is called Saponification ii) Salting out of soap: Common salt is then added to the boiling mixture. Soap is finally precipitated in the tank.

After several hours the soap rises to the top of the liquid as a ‘curdy mass’. The neat soap is taken off from the top. It is then allowed to cool down. Effect of hard water on soap Hard water contains calcium and magnesium ions (Ca + and Mg + ) that limit the cleaning action of soap.

When combined with soap, hard water develops a thin layer (precipitates of the metal ions) called ‘scum’, which leaves a deposit on the clothes or skin and does not easily rinse away. Over time, this can lead to the deterioration of the fabric and eventually ruin the clothes. On the other hand, detergents are made with chemicals that are not affected by hard water. Why ordinary soap is not suitable for using with hard water?

Ordinary soaps when treated with hard water, precipitate as salts of calcium and magnesium. They appear at the surface of the cloth as sticky grey scum. Thus, the soaps cannot be used conveniently in hard water . .

. Detergents Development of synthetic detergents is a big achievement in the field of cleansing. These soaps possess the desirable properties of ordinary soaps and also can be used with hard water and in acidic solutions. These are salts of sulphonic acids or alkyl hydrogen sulphates in comparison to soap, which are salts of carboxylic acids.

The detergents do not form precipitates with Ca + and Mg + present in hard water. So, the cleansing action of detergents is better than that of soaps. Preparation of detergents Detergents are prepared by adding sulphuric acid to the processed hydrocarbon obtained from petroleum. This chemical reaction result in the formation of molecules similar to the fatty acid in soap.

Then, an alkali is added to the mixture to produce the ‘surfactant molecules’, which do not bond with the minerals present in the hard water, thus preventing the formation of their precipitates. In addition to a ‘surfactant’, the modern detergent contains several other ingredients. They are listed as follows: i) Sodium silicate, which prevents the corrosion and ensures that the detergent does not damage the washing machine. ii) Fluorescent whitening agents that give a glow to the clothes.

iii) Oxygen bleaches, such as ‘sodium perborate’, enable the removal of certain stains from the cloth. iv) Sodium sulphate is added to prevent the caking of the detergent powder. v) Enzymes are added to break down some stains caused by biological substances like blood and vegetable juice. vi) Certain chemicals that give out a pleasant smell are also added to make the clothes fragrant after they are washed with detergents.

. . Cleansing action of soap A soap molecule contains two chemically distinct parts that interact differently with water. It has one polar end , which is a short head with a carboxylate group ( – COONa) and one non-polar end having the long tail made of the hydrocarbon chain .

The polar end is hydrophilic (Water loving) in nature and this end is attracted towards water. The non-polar end is hydrophobic (Water hating) in nature and it is attracted towards dirt or oil on the cloth, but not attracted towards water. Thus, the hydrophobic part of the soap molecule traps the dirt and the hydrophilic part makes the entire molecule soluble in water. When a soap or detergent is dissolved in water, the molecules join together as clusters called ‘ micelles ’.

Their long hydrocarbon chains attach themselves to the oil and dirt. The dirt is thus surrounded by the non-polar end of the soap molecules (Figure . ). The charged carboxylate end of the soap molecules makes the micelles soluble in water.

Thus, the dirt is washed away with the soap. Advantages of detergents over soaps Detergents are better than soaps because they: ¾ can be used in both hard and soft water and can clean more effectively in hard water than soap. ¾ can also be used in saline and acidic water. ¾ do not leave any soap scum on the tub or clothes.

¾ dissolve freely even in cool water and rinse freely in hard water. ¾ can be used for washing woollen garments, where as soap cannot be used. ¾ have a linear hydrocarbon chain, which is biodegradable. ¾ are active emulsifiers of motor grease.

¾ do an effective and safe cleansing, keeping even synthetic fabrics brighter and whiter. Biodegradable and Non-biodegradable detergents: a) Biodegradable detergents: They have straight hydrocarbon chains, which can be easily degraded by bacteria. Hydrophilic head Hydrophobic tail Aqueous soluon Soap molucules Soap solutoin Dirt Dirty cloth Figure . Cleansing action of soap b) Non-biodegradable detergents: They have highly branched hydrocarbon chains, which cannot be degraded by bacteria.

Disadvantages of Detergents . Some detergents having a branched hydro- carbon chain are not fully biodegradable by micro-organisms present in water. So, they cause water pollution. .

They are relatively more expensive than soap. Carbon and its Compounds . . Comparison between soap and detergents Soap Detergent It is a sodium salt of long chain fatty acids.

It is sodium salts of sulphonic acids. The ionic part of a soap is – COO – Na + . The ionic part in a detergent is – SO – Na + . It is prepared from animal fats or vegetable oils.

It is prepared from hydrocarbons obtained from crude oil. Its effectiveness is reduced when used in hard water. It is effective even in hard water. It forms a scum in hard water.

Does not form a scum in hard water. It has poor foaming capacity. It has rich foaming capacity. Soaps are biodegradable.

Most of the detergents are non-biodegradable. Have you noticed the term "TFM" in soap TFM means TOTAL FATTY MATTER. It is the one of the important factors to be considered to assess the quality of soap. A soap, which has higher TFM, is a good bathing soap.

Points to Remember A group or class of organic compounds related to each other by a general molecular formula constitutes homologous series. The IUPAC name of the any organic compound consist of three parts. ROOTWORD, PREFIX and / or SUFFIX . Functional group may be defined as an atom or group of atom or reactive part which is responsible for the characteristic properties of the compounds Ethanoic acid is most commonly known as acetic acid and belongs to a group of acids called carboxylic acids.

Ethanol or ethyl alcohol or simply alcohol is one of the most important members of the family of alcohols. The slow chemical change that takes place in complex organic compounds by the action of enzymes leading to the formation of simple molecules is called fermentation. Soaps are sodium or potassium salts of some long chain carboxylic acids. Detergents are sodium salts of sulphonic acids.

Thus instead of –COOH group in soaps, detergents contain –SO H group TEXTBOOK EVALUATION I. Choose the best answer. . The molecular formula of an open chain organic compound is C H .

The class of the compound is a. alkane b. alkene c. alkyne d.

alcohol . The IUPAC name of an organic compound is -Methyl butan- -ol. What type compound it is? a.