Organic Chemistry PDF

Okay, I will convert the information in the images into a structured markdown format. ### The word organic The word organic comes from the Greek language "organikos" meaning organ and is generalized to organ of living organisms. The chemistry that deals with compounds having carbon is called organ...

Okay, I will convert the information in the images into a structured markdown format. ### The word organic The word organic comes from the Greek language "organikos" meaning organ and is generalized to organ of living organisms. The chemistry that deals with compounds having carbon is called organic chemistry. ### Interesting Information: Carbon dioxide ($CO_2$), carbon monoxide ($CO$), carbonates ($CO_3^{2-}$), hydrogencarbonates ($HCO_3$), cyanides ($CN$) and cyanates ($CNO$) are inorganic compounds, though they have carbon in them. The reason is that organic compounds should have carbon directly bonded to hydrogen and carbon. The compounds which are composed of carbon element are called organic compounds. On the other hand, the compounds made of elements other than carbon are called inorganic compounds. They come from rocks and minerals. In organic compounds, carbon atoms are covalently bonded with one another and form the backbone of organic compounds. In the early nineteen centuries, chemists thought that organic compounds are obtained only from plants and animals (living or once living), but not from inorganic compounds. ### Interesting Information In 1810, Jons Jacob Berzelius said that organic compounds originated from living things (plants and animals). He added that organic compounds can be synthesized only from living matter. He thought that living things have a mysterious spiritual force called vital force (vital force theory) that was needed for preparation of organic compounds. For example, urea is made inside the body of animals and cannot be synthesized from inorganic compounds in laboratory. In 1828, a German chemist Friedrich Wohler wanted to prepare ammonium cyanate ($NH_4OCN$) from the following reaction: $AgOCN_{(s)} + NH_4Cl_{(aq)} \longrightarrow NH_4OCN_{(aq)} + AgCl_{(s)}$ He obtained white powder from the reaction mixture, which was not ammonium cyanate ($NH_4OCN$), but urea ($NH_2CONH_2$) that was previously reported in urine. Actually, the mixture had ammonium cyanate, which isomerized to urea at high temperature. In other words, we can say that Wohler synthesized urea ($NH_2-CO-NH_2$), which is an organic compound, in a laboratory by heating ammonium cyanate ($NH_4CNO$), which is an inorganic compound. $NH_4OCN \longrightarrow NH_2-CO-NH_2$ (inorganic) (organic) After the discovery of urea, Wohler wrote a letter to his mentor, Berzelius, telling him that he could make urea without the use of kidney of man and dog. He further said that ammonium cyanate is urea. Today, several organic compounds are obtained from living things, but so many organic compounds are synthesized from inorganic material in laboratory. Isomerism was discovered by Friedrich Wohler when he found that ammonium cyanate ($NH_4OCN$) and urea ($NH_2-CO-NH_2$) have same chemical formulas, but different structural formulas. The chemistry of carbon is so vast that the number of compounds formed by carbon alone are greater than the number of compounds formed by all other elements in the nature. Roughly speaking, there are almost 20 million organic compounds know so far. Some chemists thought that some vital force would have transferred to the reaction mixture from Wohler's body, but majority endorsed that a synthesis of organic compound (urea) from inorganic compound (ammonium cyanate). ## 15. 1 CATENATION The word catenation comes from a Greek word "catena," which means chain. The ability of carbon atoms to form long chains and rings is called catenation. There are some other elements which tend to show limited degree of catenation, like silicon (forming small chains) and sulphur (forming small rings). ### Importance of Catenation in Organic Chemistry Carbon is the essential part of all organic compounds. Catenation of carbon plays significant role in organic chemistry. The existence of large number of organic compounds in nature is due to the following reasons: 1. Catenation of carbon making single, double, and triple bonds. 2. Kinetic stability of organic compounds 3. Attachment of carbon with other elements. Carbon shows catenation because of its tendency to make strong carbon-carbon bonds and stable structures of molecules due to its small size. The presence of multiple bonds, attachment of atoms other than carbon / hydrogen and isomerism are the reasons behind existence of such a large number of organic compounds in nature. ## 15.2 REPRESENTATION OF ORGANIC MOLECULES Organic compounds have more complex structures than inorganic compounds, so they require more than one different type of formulae. The following different types of formulae are used for organic compounds as situation demands. ### 15.2.1 Molecular Formula For the sake of convenience, scientists thought to use specific symbols to represent elements and compounds. Such symbolic representations are employed to make chemical formulae. A chemical reaction taking place in laboratory can be shown with the help of chemical formulae on white board or notebook in order make students understand what happens in the reaction vessel. Such representation of chemical reaction with the help of chemical formulae of reactants and products is called chemical equation. A molecular formula shows the type of atoms of and the actual whole number ratio between atoms of different elements in a molecule of organic compound. The following table shows some molecular formulae of organic compounds. | Compound | Molecular formula | Compound | Molecular formula | | ------------- | ----------------- | -------- | ----------------- | | ethanol | $C_2H_6O$ | ethene | $C_2H_4$ | | ethanoic acid | $C_2H_4O_2$ | benzene | $C_6H_6$ | | glucose | $C_6H_{12}O_6$ | ethyne | $C_2H_2$ | ### 15.2.2 Empirical Formula Organic molecules may have same or different ratio between atoms in their molecular formulae. Some molecules, like ethyne ($C_2H_2$) have same number of atoms whereas others, like ethane ($C_2H_6$) have different. Empirical formula is the symbolic representation of organic compounds which shows simplest whole number ratio between elements in them. The following table shows empirical formulae with corresponding molecular formulae. #### Interesting Information Inorganic compounds have only empirical formulae as they have simple structures. | Compound | Molecular formula | Empirical formula | | ------------- | ----------------- | ----------------- | | ethanol | $C_2H_6O$ | $C_2H_6O$ | | ethanoic acid | $C_2H_4O_2$ | $CH_2O$ | | glucose | $C_6H_{12}O_6$ | $CH_2O$ | | benzene | $C_6H_6$ | $CH$ | | ethyne | $C_2H_2$ | $CH$ | Empirical formulae may misguide us in identifying organic compounds. For example, both glucose and ethanoic acid have same empirical formula "$CH_2O$" so it confuses us to differentiate between glucose and ethanoic acid. Similarly, some compounds have same empirical and molecular formulae, like sucrose ($C_{12}H_{22}O_{11}$). #### Determination of Empirical and Molecular Formulae from Combustion Analysis **Example 1:** An organic compound has percentage composition by mass, $C=38.4\\%$, $H= 4.8\\%$ and $Cl = 56.8\\%$. Calculate empirical formula of this compound. **Solution:** i. Calculate moles of each element. Moles of carbon = 38.4 / 12 = 3.2 Moles of hydrogen = 4.8 / 1.0 = 4.8 Moles of chlorine = 56.8 / 35.5 = 1.6 **The percentage by mass of an element equals to its mass.** ii. Divide all moles by the smallest value of moles to get ratio of atoms (empirical formula). Carbon = 3.2 / 1.6 = 2 Hydrogen = 4.8 / 1.6 = 3 Chlorine = 1.6 / 1.6 = 1 If we do not get whole numbers (we cannot round off the values) in step (ii), we must multiply them with smallest whole number to convert them to whole numbers. iii. The empirical formula of this compounds has 2 carbon atoms, 3 hydrogen atoms and 1 chlorine atom, i.e., $C_2H_3Cl$. ### Example 2: An organic compound has empirical formula "CH" and molecular mass 78 amu. Calculate its molecular formula. **Solution:** We know that molecular formula may be a multiple of its empirical formula so we must know that multiple (number) represented by "n." $n = \frac{molecular \ mass}{empirical \ formula \ mass}= \frac{78}{13} = 6$ We know that molecular formula = n * (empirical formula) Therefore, we can write $6(CH) = C_6H_6$. Both molecular and empirical formulae failed to provide us complete identity of organic molecules. Since a molecular formula cannot guide us in identifying functional group and pattern of bonding between atoms in organic molecules so we need other formulae that can show a more detailed pictures of organic molecules. ### 15.2.3 Structural Formulae A structural formula makes us know two things about molecules, the way of arrangement of atoms and the type of functional group in it. There are three types of structural formulae. 1. Condensed Structural Formula A condensed structural formula tells us about the relative positions of all atoms in a molecule, without showing single covalent bonds. Each carbon atom in this formula is shown individually with hydrogen atoms attached to it. The branches, functional groups and repeating methylene groups in the middle of molecules are shown in brackets. The condensed structural formula of acetic acid ($CH_3COOH$) shows that three hydrogen atoms are bonded to first carbon and the remaining one is attached to one of the two oxygen atoms. It also indicates that carboxyl group (COOH) is the functional group in acetic acid molecule. **Key Information:** The side chain or functional group is shown in bracket, with the carbon to which it is attached, in the condensed structural formulae of organic compounds. | Alkane | Condensed structural formula | Alkane | Condensed structural formula | | ------- | ----------------------------------- | ------- | ---------------------------------- | | methane | $CH_4$ | hexane | $CH_3(CH_2)_4CH_3$ | | ethane | $CH_3CH_3$ | heptane | $CH_3(CH_2)_5CH_3$ | | propane | $CH_3CH_2CH_3$ | octane | $CH_3(CH_2)_6CH_3$ | | butane | $CH_3(CH_2)_2CH_3$ | nonane | $CH_3(CH_2)_7CH_3$ | | pentane | $CH_3(CH_2)_3CH_3$ | decane | $CH_3(CH_2)_8CH_3$ | **2. Full Structural Formula** A full structural formula indicates all atoms and bonds among them in a molecule. It is two-dimensional formula and also called 2D displayed formula. **Key Information:** A 2D formula tells us about planar molecules showing arrangement of atoms in x and y planes only. ethane is described as H-C-C-H, where each C has 3 H attached to it. ethanol is described as H-C-C-OH, where each C has 3 H attached to it. **3. Skeletal Formula** Some organic molecules are very large and complex, so it is quite difficult to draw their structures. Skeletal formula is the most easy-to-draw representation for complex organic molecules. In skeletal formula, only lines are drawn where each end and vertex of the line is assumed to represent carbon atoms, unless another atom, like oxygen or halogen etc. Each carbon atom is assumed to be bonded to enough hydrogen atoms to complete its valency. **Key Information:** * In skeletal formula, carbon and hydrogen atoms are not shown. * Double and triple bonds between carbon atoms are shown in skeletal formula. * Functional group is also shown. butane is represented by 4 lines connected, shaped like a zig-zag. butan-2-ol is the same and has OH on the second carbon. **4. Stereochemical Formulae** The 3D displayed formula of molecules gives complete picture about all types of bonds in a molecule but tells us nothing about arrangement of atoms in molecules in three-dimensions. Chemists needed formula that could give structure of molecules in space with atoms in x, y and z planes as shown. Key for Bonds: * aling the plane (———— * out of th plane ( )wedge * inside the plane ( ) | Name | Molecular Formula | Condensed Structural Formula | Displayed Formula | Skeletal Formula | | ---------- | ----------------- | ----------------------------- | ------------------------------------------------------------------------------------------------------------------------------------ | ---------------- | | Propane | $C_3H_8$ | $CH_3CH_2CH_3$ | H H H H-C-C-C-H H H H | Zig-zag of 3 lines | | Propene | $C_3H_6$ | $CH_3CH = CH_2$ | H H H-C-C=C | | | Propan-2-ol | $C_3H_8O$ | $CH_3CH(OH)CH_3$ | HOH H-C-C-C-H H H H | Zig-zag of 3 lines, with OH connected to center | | Propanal | $C_3H_6O$ | $CH_3CH_2CHO$ | H HOH-C-C-C-H H H | Zig-zag of 3 lines one has a double bond at the end | | Propanone | $C_3H_6O$ | $CH_3COCH_3$ | HO H-C-C-C-H H H | Zig-zag of 3 lines and a double bond on the sides | ### Concept Assessment Exercise 15.1 1. Draw condensed, displayed and skeletal formulae of the following compounds: i. ethene ii. ethanol iii. butanone iv. ethanal 2. Draw the 2D displayed formulae and skeletal formulae of: i. 2-methylpentane ii. 2,4-dimethylheptane iii. 3,3,5-trimethyloctane iv. 2,2-dimethypropane ### 15.3 FUNCTIONAL GROUP An atom or group of atoms which is attached to carbon chains or rings and determines the characteristic properties of organic compounds is called functional group. All organic compounds have two parts: a reactive functional group and a relatively unreactive carbon network. For example, hydroxyl group (-OH) and carboxyl group (-COOH) are the functional groups of alcohols and carboxylic acids respectively. Since chemical reactions take place on the functional group we can say chemical properties of organic compounds depend on functional group. Moreover, double and triple bonds determine the properties of alkenes and alkynes respectively, so they are included in functional groups. ### 15.3.1 Homologous Series Since organic compounds have very large number so we cannot study them individually. We need to classify them into different homologous series which help us predict the properties of all organic compounds individually. The group of organic compounds which have the same functional group but different length of carbon chain is called homologous series. Some important homologous series are alkanes, alcohols and aldehydes. Homologous series have the following features. Key Information: A general formula determines the molecular formula of organic compounds having "n" or "m" number of carbon atoms. It is applied to monofunctional organic compounds only. 1. Each homologous series has its own functional group. 2. Each member of homologous series differs from the next member by one methylene group ($CH_2$) group. 3. Each homologous series has its own general formula. For example, the general formulas of alkanes, alkenes and alcohols are $C_nH_{2n+2}, C_nH_{2n}$ and $C_nH_{2n+1}OH$, respectively. 4. All members of homologous series have similar chemical properties. 5. A homologous series has gradual change in their physical properties with changing the size of carbon chain. 6. They have similar method of preparation. Interesting Information: Alkanes is a homologous series with no function group. The given general formula are dedicated to open chain alkanes and alkenes. The document includes a table of homologous series and functional groups as well. Here are a few entries: | Homologous Series | General Formula | Functional Group | Example | | :------------------- | :--------------------- | :------------------- | :--------------------- | | Alkanes (R-H) | $C_nH_{2n+2}$ | N/A | $CH_3-CH_3$ (ethane) | |Alkenes | $C_nH_{2n}$ | Double bond | $H_2C=CH_2$ (ethene) | |Alkynes | $C_nH_{2n-2}$ | Triple bond | H-C=-H (ethyne) | | Alcohols (R-OH) | $C_nH_{2n+1}OH$ | Hydroxyl group | $CH_3CH_2OH$ (ethanol) | |Ethers (R-O-R) | $C_nH_{2n+1}OC_mH_{2m+1}$ | Ether group | $CH_3-O-CH_3$ (methoxymethane) | | Amines (R-NH2) | $ C_nH_{2n+1}NH_2$ | Amine group | $CH_3NH_2$ (methylamine) | |Nitriles | $C_nH_{2n+1}CN$ | Nitrile group | $ CH_3CN$ (ethanenitrile) | | Aldehydes | $C_nH_{2n+1}CHO$ | Aldehyde group | $CH_3CHO$ (ethanal) | |Ketones | $C_nH_{2n+1}COH_m{2m+1}$ | Carbon group | $ CH_3COCH_3$ (propanone) | |carboxylic acid | $C_nH_{2n+1}COOH$ | Carboxyl group | $ CH_3CH_2COOH$ (propanoic acid) | | Esters(R-O-R) | $C_nH_{2n+1}COC_mH_{2m+1}$ | ester group | $CH_3COOCH_2CH_3$ (ethylethanoate) | | Acid halide | $C_nH_{2n+1}COX$ | Acid halide | $CH_3COCl$ (ethanoyl chloride) | |Arenes | $C_nH_{2n-6m}$ | phenyl group | $C_6H_5CH_2CH_3$ (ethylbenzene)| ### Concept Assessment Exercise 15.2 Write the general formulae and functional groups of the following homologous series i. alcohols ii. Aldehydes iii. Ketones iv. ethers V. carboxylic acids vi. esters vii. amines viii. nitriles ### 15.3.2 Hydrocarbons The compounds which have only carbon and hydrogen elements in their molecules are called hydrocarbons. In hydrocarbons, the carbon atoms act like the backbone whereas hydrogen atoms act like skin of molecules. Alkanes are the simplest among all organic compounds because they have no functional group, just a carbon skeleton. They are the least reactive organic compounds because of two reasons: 1. The C-C and C-H bonds are very strong and difficult to be broken. 2. The C-C and C-H bonds are non-polar so cannot be attacked by other polar reagents, like acids, bases, oxidizing and reducing agents etc. | Bond | Bond energy (kJ/mol) | Bond | Bond energy (kJ/mol) | | :---- | :------------------- | :---- | :------------------- | | C-C | 346 | Si-Si | 222 | | N-N | 167 | P-P | 201 | | O-O | 142 | S-S | 226 | Broadly, hydrocarbons are classified into two categories, saturated and unsaturated hydrocarbons. ### 15.3.3 Saturated Hydrocarbons Saturated hydrocarbons have only single covalent bonds between carbon atoms in their molecules. All alkanes and cycloalkanes include in saturated hydrocarbons. The word "saturated" is used because each carbon atom is bonded to four atoms so carbon atoms have reached their maximum combining capacity. The following are some examples of saturated hydrocarbons. Images of compounds are shown, including: * Ethane ($C_2H_6$) * Butane ($C_4H_{10}$) * Cyclobutane ($C_4H_8$) * Cyclopentane ($C_5H_{10}$) ### 15.3.4 Alkyl Group (R-) It is a group obtained by removing any one hydrogen atom from alkanes. Alkyls are named by replacing the suffix "ane" of alkane with "yl" which means that root name of corresponding alkane is followed by the suffix "yl". Primary hydrogens are shown blue, secondary red and tertiary green.(Image displays structure but I cannot recreate this document type) **Here are the examples** * Methane ($CH_4$) becomes methyl ($CH_3$) * Ethane ($CH_3CH_3$) becomes ethyl ($CH_3CH_2$) * Propane ($CH_3CH_2CH_3$) becomes n-propyl or isopropyl ($CH_3CH_2CH_2CH_3$) Key Information: * Primary carbon is further attached to one carbon atom or none, secondary carbon is bonded further to two carbon atoms whereas tertiary is attached further to three carbon atoms. * Primary hydrogen atoms are attached to primary carbon, secondary to secondary carbon and tertiary to tertiary carbon atom. ### 15.3.5 Unsaturated Hydrocarbons The word "unsaturated" is used for those hydrocarbons in which more atoms can be added to the carbon atoms. Unsaturated hydrocarbons are those which have one or more carbon-carbon double or triple bonds. Example are alkenes and alkynes. Since each double bonded carbon is attached to three atoms so it has the ability to bond one other atom. Similarly, a triply bonded carbon is bonded to two atoms and can bond to two more atoms.. Images of compounds shown: * Propene * Propyne * Cyclobutene ### 15.3.6 Terminology Associated with Naming Organic Compounds For naming organic compounds, we must familiarize ourselves with some important terms. 1. **Prefix**. It may be a branch or substituent attached to the longest carbon chain. For example, alkyls and halo groups etc. 2. **The stem or root name**. The stem name of organic molecules indicates the number of carbon atoms in the longest carbon chain. For example, meth, eth and prop etc. 3. **Suffix of root name**. There is an ending (suffix) to root name, like an, en or yn which reflects whether there is single, double or triple bond in the parent chain of molecule or not. 4. **Suffix**. It is the last part of an organic molecule which indicates the family name. There is an image, and here an explanation of what it is saying... * it shows substituents and position of the principal chain, indicated by "Prefix" * shows saturation and unsaturation in parent chain, indicates by "Suffix of Root Name" (an, en, yn). * indicates family name, indicated by "Suffix of Principal Group". * and "Root/Stem Name" shows number of carbon Adams in parent chain. | Class/family | Prefix/Suffix | Example | | :---------------- | :------------ | :------------------------------------------------------------------------------------------------------- | | Alkanes | Suffix, ane | $H_3CH_2CH_2CH_3$ (butane) | | Alkenes | Suffix, ene | $CH_3CH=CHCH_3$ (but-2-ene) | | Alkynes | Suffix, yne | $CH_3CHC \equiv CH$ (but-1-yne) | | Halogenoalkanes | Prefix, halo | $CH_3CH(Cl)CH_3$ (2-chloroethane) | | Alcohols | Suffix, ol | $CH_3CH(OH)CH_2CH_2CH_3$ (pentan-2-ol) | | Ethers | Prefix = alkoxy | $CH_3OCH_2CH_3$ (methoxyethane) | | Aldehydes | Suffix, al | $CH_3CH_2CHO$ (propanal) | | Ketones | Suffix, one | $CH_3CH_2(CO)CH_2CH_2CH_3$ (pentan-2-one) | | Amines | Suffix, amine | $CH_3CH_2NH_2$ (ethylamine) | | Nitriles | Suffix, nitrile | $CH_3CH_2CN$ (propanenitrile) | | Carboxylic acid | Suffix, oic acid | $CH_3CH_2COOH$ (propanoic acid) | | Acid halides | Suffix, oyl halide | CH3COCl (ethanoyl chloride) | | Amides | Suffix. amide | $CH_3CONH_2$ (ethanamide) | | Arenes (complicated class) | Suffix, benzene Prefix, phenyl (varies with compounds) | $C_6H_5CH_3$ (methylbenzene) | ### Used Root Names in IUPAC Nomenclature | No of Carbon | Root Name | No of Carbon | Root Name | | ------------ | --------- | ------------ | --------- | | one | meth- | six | hex- | | two | eth- | seven | hept- | | three | prop- | eight | oct- | | four | but- | nine | non- | | five | pent- | ten | dec- | ### NOMENCLATURE OF ALIPHATIC ORGANIC COMPOUNDS Aliphatic organic compounds have straight chain or branched chain molecules. Cyclic molecules, except benzene are also included in aliphatic compounds. They may be both saturated and unsaturated. There are millions of organic compounds, many with quite complex structures, which are difficult to be named. Key Information * The systematic names of all homologous series, except carboxylic acid are written as one word, like Salman * The non-systematic names or trivial names are still used for some compounds in specific situations. The International Union of Pure and Applied Chemistry (IUPAC) is the universally-recognized authority on naming organic and inorganic compounds. In this topic, we will bring only organic compounds under consideration. It provides some internationally accepted rules to chemists for giving systematic names to organic compounds. **15.4.1 Nomenclature of Alkanes** Alkanes provide the basis for nomenclature of organic compounds so we apply the IUPAC rules on alkanes first and then extend them to other families of organic compounds. Common (Trivial) Names of Alkanes * $CH_3CH_2CH_2CH_2CH_3$ n-pentane * $CH_3CH(CH_3)CH_2CH_3$ isopentane * $CH_3C(CH_3)_2CH_3$ neopentane Systematic Names of Alkanes The following rules are applied while giving systematic (IUPAC) names to alkanes. 1. Identify the longest continuous carbon chain (parent chain) in the given compound. The number of carbon atoms in the longest chain gives us root name of the compound. Consider the following three structures (red carbons form principal chain). In the given three molecules, there are seven carbon atoms in the parent chain so the root name is "hept". Since there are all single covalent bonds between carbon atoms in the three molecules so they belong to alkanes family with suffix "ane." Thus the systematic name of the given compounds is heptane. All the three structures are straight chain molecules of heptane and identical in all respects. 2. Identify the substituents (branches} or side chains and their position (location) and use them as the prefixes of systematic names- In alkanes, alkyl groups are the substituents attached to principal chain. Key Information: *in systematic names separated hyphens numbers commas 3. If there are two or more identical substituents attached to the parent chain, then use the prefixes di, tri and tetra etc with their names. The document lists the names and structures of complex alkanes, including. 3,3 -dimethylheptane: and 3,4-dimethyloctane The document describes 3,3,5-trimethyloctane. If there are two or more different substituents in a molecule , put corresponding alphabetical locant alphabetical. 1. $CH2CH(CH3)CH2CHCH(CH3)CH2CH3$ **5-ethyl -3-methylocatane** ## 15.4.2 Nomenclature of cycloalkanes The following rules are used for naming cycloalkanes according to IUPAC system 1. While naming cycloalkanes, their stem name is prefixed by “cyclo”. 2. In case of substituted cycloalkanes, the names of substituents are but before the name of cycloalkane along with their position on the carbon ring. ### 15.4.3 Nomenclature of Alkenes and Alkynes Alkenes and alkynes follow the same rules of IUPAC nomenclature as alkanes do but they have functional group (carbon-carbon double and triple bonds) which need to be located and put in the systematic name. 1. The parent chain of alkenes and alkynes must have double and triple bonds respectively. 2. The position of double and triple bond must follow the root name immediately which is the followed by the suffixes "ene" for alkenes and "yne" for alkynes. 3. CH =CH : ethene 4. CH3-CH-CH: propene 5. The document references 4-methylpent-1-ene, and 5-methylhex-1-yne A, add di, tri the stem. 1 add di, tri the stem. 4 CH2=CH-CH2. C(CH ### 15.4.4.nomenclature Halogenoalkanes Halogenoalkanes are those organic compounds in which one. or more hydrogen atoms of alkanes. * * * Here are some more points: *The position of functional group is shown by number in the carbon - and "al of aldehydes • There methylbutanal