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A  nucleophilic substitution  ( S N ) is a class of organic chemical reactions in which an electron-rich chemical species (known as a nucleophile) replaces a functional group (called the leaving group or  LG ) within another electron-deficient molecule (known as the electrophile) referred to as the substrate. This may engage either a one- ( 1 ) or two-step ( 2 ) mechanism (unimolecular and bimolecular respectively). Aromatic rings are usually nucleophilic, but some aromatic compounds do undergo nucleophilic substitution especially if  o-,p -positions carry strong electron withdrawing groups ( EWGs ). Question: Predict the major product(s) of the following reaction  and tell which one would be faster and why: Click/tap to enlarge the image Solution infographic: Click/tap to enlarge the image This is a nucleophilic substitution in the side chain of the aromatic ring only! Neat nucleophilic substitution❓ Let Chemaficionado know in the comments below or at mychemi...

Green chemistry is focused on the design of products and processes that minimize or eliminate the use and generation of hazardous materials (HazMat). There exist two related terms, viz ., atom economy ( AE ) and environmental factor ( E -factor). % AE = [(Stoichiometric mass of the desired product) / (Mass of a stoichiometric mixture of reactants)] x 100 Simply put, a large AE means a little waste and reduces raw material costs and environmental impact. E -factor = (Mass of waste produced) / (Mass of product obtained) The mass of the water is excluded if the reaction or process produces waste water. However, the masses of substances dissolved in the water are included. A small E -factor is wanted. For real-time monitoring of the impact of modifications to a synthesis or industrial process, the E -factor is chiefly valuable. Most laboratory and industrial processes also utilize a solvent and an excess of one or more of the reagents in the reaction, which increase the am...

Chemistry is quite logical but there exist (annoying) exceptions . For one, water freezes at 0 0 C ( 1 atm ); however, water has the maximum density at 4 0 C . This makes liquid water denser than ice, which is why ice floats on water! This is known as the anomalous expansion of water. Wheel of chemistry anomalies: Click/tap to enlarge the image EC = Electron configuration Erratic exceptions❓ What other wheel(s) 🎡 of chemistry would you like to see❓ Let Chemaficionado know in the comments below or at mychemistryhomework@gmail.com ❗ References: (1)      Brown, C.; Ford, M.  Higher Level Chemistry , 2nd ed.; Pearson Education: Harlow, Essex, 2014. ‌ (2)      Ncert.  Chemistry : Textbook for Class XI - Part.I ; National Council Of Educational Research And Training: New Delhi. (3)    Mikulecky, P.; Michelle Rose Gilman; Brutlag, K.  AP Chemistry for Dummies ; Wiley Publishing, Inc: Hoboken, Nj, 2009.

Alcohol dehydration  is an important reaction in organic chemistry as it opens the possibility of numerous derivatives. Regiochemistry is reagent dependent. Concentrated sulfuric acid promotes  E1  elimination; however, may trigger a rearrangement via hydride/alkyl shift, ring expansion/contraction as it involves carbocation intermediate(s). Question: Predict the major product(s) of the following reactions: Click/tap to enlarge the image Solution infographic: Click/tap to enlarge the image E1  = Elimination unimolecular Dandy dehydration❓ Let Chemaficionado know in the comments below or at mychemistryhomework@gmail.com ❗ References: (1)      Rearrangement reaction . Wikipedia. https://en.wikipedia.org/wiki/Rearrangement_reaction. (2)      Wikipedia Contributors.  Elimination reaction . Wikipedia. (3)      Brown, C.; Ford, M.  Higher Level Chemistry , 2nd ed.; Pearson Education: Harlow, Essex, 2014. (4)  ...

Multistep synthesis  is the artificial execution of multiple organic chemical reactions to obtain one or more products by physical and chemical manipulations. Retrosynthetic analysis is a problem-solving approach in the organic syntheses, achieved by transforming a target molecule into simpler precursor structures regardless of any potential reactivity/interaction with reagents, and repeated until a simple or commercially available structure is reached, which can be used as a starting material to synthesize the target molecule. Question: How would you do the following transformation? Click/tap here to enlarge the image Solution infographic: Click/tap here to enlarge the image Let's keep in mind that any multistep synthesis is possible via several routes ❗Questions ❓ Let Chemaficionado know in the comments below or at mychemistryhomework@gmail.com ❗ References: (1)      Wikipedia Contributors.  Chemical synthesis . Wikipedia. https://en.wikipedia.org/wiki/Chemi...

The separation science did not begin with sophisticated analytical instruments but did in wet labs. A separation process is a scientific method or technique that converts a mixture or a solution of chemical substances into two or more distinct product mixtures to obtain purity. Separation may involve physical and/or chemical processes. Question: How would you separate a mixture of 1,3-Dinitrobenzene, 3-Nitroaniline, 3-Nitrobenzoic acid and 3-Nitrophenol? Solution infographic: Click/tap to enlarge the image For a whopping wheel 🛞 of separation processes, click HERE . Satisfactory separation ❓ Let Chemaficionado know in the comments below or at mychemistryhomework@gmail.com ❗ References: (1)      Brown, C.; Ford, M.  Higher Level Chemistry , 2nd ed.; Pearson Education: Harlow, Essex, 2014. (2)      Ncert.  Chemistry : Textbook for Class XI - Part.II ; National Council Of Educational Research And Training: New Delhi. (3)    ...

A reducing agent may or may not be selective in an organic reaction. If Hydrogen gas is passed through an organic compound (often dissolved in an organic solvent under moderately high or high temperature and/or pressure) in presence of a transition metal catalyst (or its compound), reduction ( Red ) occurs. Both Lithium aluminum hydride, LiAlH 4 or Li[AlH 4 ] ( LAH ) and Sodium borohydride ( aka Sodium tetrahydridoborate or Sodium tetrahydroborate), NaBH 4 or Na[BH 4 ] are inorganic compounds, the former being a stronger reducing agent. If the product has a new chiral center, stereoisomers may be obtained. Question: How would you do the following transformations (only one-step for each)? Click/tap to enlarge the image Solution infographic: Click/tap to enlarge the image Randomness of the reducing agents❓ Let Chemaficionado know in the comments below or at mychemistryhomework@gmail.com ❗ References: (1)      Wikipedia Contributors.  Hydrogenation ....

Reactions in organic chemistry are diverse, ain’t they? An organic compound may typically undergo addition (all in, none out), elimination (all out, none in), substitution (some out, some other in) or rearrangement (change in constitution) reaction. There are many sub-types. Addition ( A ) or substitution ( S ) can be electrophilic ( E ) or nucleophilic ( N ) like A E , S N , A N or S E . Substitution or elimination ( E ) can be unimolecular ( 1 ) or bimolecular ( 2 ) like S N 1, S N 2, E1 or E2 . The reaction can be in the ring or in the side-chain depending on the reagent used (reagent dependent regiochemistry). A rearrangement may be triggered via hydride/alkyl shift, or ring expansion/contraction. Question: Predict the major product(s) of the following reaction: Click/tap to enlarge the image Solution infographic: Click/tap to enlarge the image Reaction riddles❓ Let Chemaficionado know in the comments below or at mychemistryhomework@gmail.com ❗ References: (1) ...

Mole  is a quantity proportional to the number of elementary entities of a substance. Since equal volumes of all gases, at the same temperature and pressure, have the same number of molecules according to the  Avogadro’s law , molar volumes ( 22.4 L or dm 3 ) of all gases, at the standard (normal) temperature and pressure ( STP/NTP; 0 0 C  (or  273 K )  & 1 atm  respectively), have the same number of molecules ( N A  =  6.022 x 10 23 ) . The mole concept applies to molecules, ions, ion pairs, atoms, electrons . Wheel of moles: Click/tap to enlarge the image Mesmerizing moles❓ What other wheel(s) 🎡 of chemistry would you like to see❓ Let Chemaficionado know in the comments below or at mychemistryhomework@gmail.com ❗ References: (1)      Brown, C.; Ford, M.  Higher Level Chemistry , 2nd ed.; Pearson Education: Harlow, Essex, 2014. ‌ (2)      Ncert.  Chemistry : Textbook for Class XI - Part.I ; National...

A coordination complex is a chemical compound made of a central atom/ion (usually metallic) called the coordination center and a surrounding array of bound molecules/ions referred to as ligands or complexing agents. Coordination complexes typically having transition metals or d -block elements in the periodic table are known as metal-ligand complexes ( MLCs ). A spectrochemical series is a list of ligands ordered by ligand-field ‘strength’ (energy). Spectrochemical series (in the increasing order of the ligand-field strength): I −  <  B r −  <  S 2−  <  S CN −  <  C l −  <  N O 3 −  <  N 3 −  <  F −  <  O H −  <  C 2 O 4 2−  <  O 2−  <  H 2 O <  N CS −  <  C H 3 CN <  E DTA 4-  <  p y <  N H 3  <  e n <  b ipy <  p hen <  N O 2 −  <  P Ph 3  ...

A phase diagram is a type of chart used to display conditions (pressure, temperature, etc.) at which thermodynamically distinct phases ( viz ., solid, liquid or gaseous states) occur and coexist at equilibrium. Physical chemistry, engineering, mineralogy, and materials science utilize phase diagrams. Question: Refer to the phase diagram shown below: Click/tap to enlarge the image Label the diagram. If the temperature decreases from 100 0 C to 60 0 C at a constant pressure of 1.5 atm , which process occurs? If the pressure increases from 0.5 atm to 1.5 atm at a constant temperature of 10 0 0 C , which process occurs? What is the normal boiling point of the substance approximately? Solution infographic: Click/tap to enlarge the image bp = Boiling point, mp = Melting point Perplexed or pleased by the phase diagram solution❓ Let Chemaficionado know in the comments below or at mychemistryhomework@gmail.com ❗ References: (1)      Phase diagram . Wikipedia. http...

Diastereoselective nucleophilic addition ( A N ) is not accomplished easily; however, the use of an unconventional reagent may pave the way for a successful end product. Diastereomers ( aka diastereoisomers) are constitutionally identical molecules non-mirror images of each other, can have different biological activities, potencies or toxicities, and occur when two or more stereoisomers of a compound have different configurations at one or more (but not all) of the corresponding stereocenters and are not mirror images of each other. An A N reaction is an addition reaction where an organic compound with an electrophilic double/triple bond reacts with a nucleophile s.t. the double/triple bond undergoes a cleavage. An allyl group is a nucleophile which can add to an α -oxy carbonyl ( C=O ) compound in two ways; either opposite to the α - O (making syn -adduct) or same side as the α-O (producing anti -adduct). The high chelation tendency of the α -oxy group typically yields the syn -a...

Carbonyl compounds are popular as substrates for condensation reactions. The presence of an  α -hydrogen is a required condition. These reactions are often base-catalyzed. What if  an   α -hydrogen is not present? What if the base is concentrated? What are the possibilities depending on the substrate? Question: Predict the major product(s) of the following reaction: Click/tap to enlarge the image Solution infographic: Click/tap to enlarge the image Ridiculous reagents❓ Let Chemaficionado know in the comments below or at mychemistryhomework@gmail.com ❗ References: (1)      Wikipedia Contributors.   Cannizzaro reaction . Wikipedia. ‌ (2)      Graham, T. W.; Fryhle, C. B.; Snyder, S. A.  Organic Chemistry. ; Hoboken, Nj John Wiley Et Sons, Inc, 2016. (3)      Brown, C.; Ford, M.  Higher Level Chemistry , 2nd ed.; Pearson Education: Harlow, Essex, 2014. (4)      Ncert.  Chemistry : Textboo...