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An organic reaction in which an atom attached to an aromatic system (usually hydrogen) is substituted by an electrophile is referred to as  electrophilic aromatic substitution  ( S E Ar  or  EAS ). One of the most important  EASs  is nitration. Question: Predict the major product(s) of the following reaction: Click/tap to enlarge the image Solution infographic: Click/tap to enlarge the image Does the solution infographic above make sense❓ Let Chemaficionado know in the comments below or at mychemistryhomework@gmail.com ❗ References: (1)      Wikipedia Contributors.  Electrophilic aromatic substitution . Wikipedia. https://en.wikipedia.org/wiki/Electrophilic_aromatic_substitution. (2)      Chouhan, M. S.  Advanced Problems in Organic Chemistry for JEE , 11th Ed.

The first law of thermodynamics states that, when energy passes into or out of a system (as work, heat, or matter), the system's internal energy changes in accordance with the law of conservation of energy. No work is done as the chemical reaction is carried out at constant volume in a bomb calorimeter. Question: 1 g of graphite is burnt in a bomb calorimeter in excess of oxygen at 298 K & 1 atm according to the following equation: C(s) (graphite) + O 2 (g) → CO 2 (g) During the reaction, temperature rises from 298 K to 299 K . If the heat capacity of the bomb calorimeter is 20.7 kJ/K , what is the enthalpy change for the above reaction at 298 K & 1 atm? Solution: Click to enlarge the image q = Heat, C v = Heat capacity at constant volume,   Δ T = Change in absolute temperature, w = Work done ,  Δ U =  Change in internal energy,   Δ H =  Change in enthalpy,   Δ n g  =  Change in moles of gaseous molecules,...

The  carbocation stability  is critical to the success of many reactions involving organic compounds. The stability of a carbocation depends on multiple factors, say, its participation in resonance, presence on a substituted carbon ( α─H ) or existence in an aromatic ring. However, there may exist a carbocation promoter and/or some other driving force! Question: Predict the major product(s) of the following reaction: Click/tap to enlarge the image Solution infographic: Click/tap to enlarge the image S N 1 = Substitution nucleophilic unimolecular, rt = Room temperature Are you fond of carbocation stability❓ Let Chemaficionado know in the comments below or at mychemistryhomework@gmail.com ❗ References: (1)     Carbocation . Wikipedia. https://en.wikipedia.org/wiki/Carbocation. (2)     Wikipedia Contributors.  Le Chatelier’s principle . Wikipedia. https://en.wikipedia.org/wiki/Le_Chatelier%27s_principle. ‌(3)      Wikipedia ...

A nucleophilic addition ( 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. Let’s recall that nucleophilicity and basicity are not the same thing! Question: Predict the major product(s) of the following reaction: Click/tap to enlarge the image Solution infographic: Click/tap to enlarge the image Electrophile versus nucleophile, basicity versus nucleophilicity; go fight ❗ Let Chemaficionado know in the comments below or at mychemistryhomework@gmail.com ❗ References: (1)      Nucleophilic addition . Wikipedia. https://en.wikipedia.org/wiki/Nucleophilic_addition. ‌(2)    Chouhan, M. S.  Advanced Problems in Organic Chemistry for JEE , 11th Ed.

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: Predict the major products of the following reactions: Click/tap to enlarge the image Solution infographic: Click/tap to enlarge the image Substrate Products by   NaBH 4 LAH Aldehydes 1 0 alcohols 1 0 alcohols Ketones 2 0 alcohols 2 0 alcohols Esters No rxn 1 0 alcohols Carboxylic acids No rxn 1 0 alcohols Acid halides 1 0  alcohols 1 0 alcohols Acid anhydrides 1 0  alcohols 1 0 alcohols Amides ...

Dalton's law ( aka Dalton's law of partial pressures ) states that the total pressure exerted is equal to the sum of the partial pressures of the individual gases in a mixture of non-reacting ideal gases. Partial pressures of the gases in a mixture tell us the relative number of particles or moles of the gases in that mixture. Question: N 2 (g) & H 2 (g) are added to a previously evacuated container and react at a constant temperature according to the following chemical equation: N 2 (g) + 3H 2 (g) → 2NH 3 (g) If the initial pressure of N 2 (g) was 1.2 atm , and that of H 2 (g) was 3.8 atm , what is the partial pressure of NH 3 (g) when the partial pressure of N 2 (g) has decreased to 0.9 atm ? Solution: Click/tap to enlarge the image Got the pressure relieved❓ Let Chemaficionado know in the comments below or at mychemistryhomework@gmail.com ❗ Reference: Wikipedia Contributors.  Dalton’s law . Wikipedia. https://en.wikipedia.org/wiki/Dalton%27s_law.

Vapor pressure or equilibrium vapor pressure, an indication of a liquid's thermodynamic tendency to evaporate, is the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases (solid/liquid) at a given temperature in a closed system. Boyle's law aka the Boyle–Mariotte law or Mariotte's law states that the absolute pressure exerted by a given mass of an ideal gas is inversely proportional to the volume it occupies if the temperature and amount of gas remain unchanged within a closed system. Question: A liquid is in equilibrium with its vapor in a sealed container at a fixed temperature. The volume of the container is suddenly increased. a ) What is the initial effect of the change on vapor pressure? b ) How do rates of evaporation and condensation change initially? c ) What happens when equilibrium is restored finally and what will be the final vapor pressure? Solution:   Click to enlarge the image Did I vapor you to death now or y...

A nucleophile (nucleus-loving or positive-seeking) is a chemical species (molecules/ions) that forms bonds by donating an electron pair, which may be a free pair of electrons or at least one π ─bond. A nucleophile is also a Lewis base , which is any species that has a filled orbital containing an electron pair which is not involved in bonding but may form a coordinate/dative bond with a Lewis acid to form a Lewis adduct or may accept a proton. However, the two are not the same thing! Let's figure it out. Click to enlarge the image TS = Transition state Are you in love with nucleophiles ❓ You must be an electrophile then. 😄 Let Chemaficionado know at mychemistryhomework@gmail.com ❗ References: (1)      Nucleophile . Wikipedia. https://en.wikipedia.org/wiki/Nucleophile. (2)      Wikipedia Contributors.  Lewis acids and bases . Wikipedia.

4-Toluenesulfonyl chloride or p -Toluenesulfonyl chloride aka Tosyl chloride , abbreviated as TsCl/TosCl , is a reagent widely used in organic synthesis. Since ─ OTs (tosyl) is a better leaving group ( LG ) than ─ OH (hydroxy), a tosylate is generated to facilitate a substitution nucleophilic bimolecular reaction ( S N 2 ). Question: Predict the major product(s) of the following reactions: Click/tap to enlarge the image Solution infographic: Click/tap to enlarge the image Exciting chemistry of tosylates❓ Let Chemaficionado know in the comments below or at mychemistryhomework@gmail.com ❗ References: (1)      Wikipedia Contributors.  4-Toluenesulfonyl chloride . Wikipedia. (2)      Chouhan, M. S.  Advanced Problems in Organic Chemistry for JEE , 11th Ed.

The standard enthalpy of formation of a compound ( Δ f H Ѳ ) is the change of enthalpy (heat) during the formation of one mole of the compound/substance from its constituent elements in their reference/standard states. The bond dissociation energy ( BDE, D 0 , or DH° ) is the standard enthalpy change when a chemical bond A−B is cleaved by homolysis to produce radical fragments A & B . BDE is one measure of the bond strength & temperature-dependent. The BDE differs from the bond energy ( BE aka mean bond, bond enthalpy, average bond enthalpy, or bond strength) except for diatomic molecules. While the BDE is the energy of a single bond, the BE is the average of all the BDEs of the bonds of the same type for a given molecule. IUPAC (international union of pure and applied chemistry) defines BE in the gas-phase usually at a temperature of 298.15 K . Mnemonic :  B-FOR : Bonds  B roken  B e FOR e  (sounds almost like  B-FOR ) bonds  FOR me...

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 ). Chelation, a type of bonding and sequestration of metal atoms, involves ≥ 2 separate dative/coordinate covalent bonds between a ligand and a metal atom, forming a ring. Question: Arrange the following in the increasing order of stability: [Ni(tn) 3 ] 2+ , [Ni(en) 3 ] 2+ & [Ni(NH 3 ) 6 ] 2+ . Solution infographic: Click to enlarge the image Complexes look simple now❓ Let Chemaficionado know at mychemistryhomework@gmail.com ❗ References: (1)    Wikipedia Contributors.  Coordination complex . Wikipedia. https://en.wikipedia.org/wiki/Coordination_complex. (2)    Wikipedia Contributo...

Interstitial sites/holes/voids in crystallography are the empty space that exists between the close-packing of atoms (typically considered as spheres) in the crystal structure. Close-packing of spheres in geometry is a dense, infinite, regular arrangement of congruent, identical spheres in an arrangement ( aka lattice). Question: Atoms of element B form hcp lattice and those of the element A occupy 2/3rd of tetrahedral voids. What is the formula of the compound formed by the elements A & B ?  Solution: Click to enlarge the image How is it❓ Let Chemaficionado know at mychemistryhomework@gmail.com ❗ References: (1)      Wikipedia Contributors.  Close-packing of equal spheres . Wikipedia. https://en.wikipedia.org/wiki/Close-packing_of_equal_spheres. (2)    Wikipedia Contributors.  Interstitial site . Wikipedia. (3)      Ncert.  Chemistry : Textbook for Class XI - Part.I ; National Council Of Educational Rese...

The metathesis reactions classification ! Olefin/alkene metathesis is an organic reaction that entails the redistribution of alkenes fragments by the breaking and formation of C=C double bonds catalyzed by transition metals. It often creates fewer undesired by-products and hazardous wastes than alternative organic reactions b ecause of the relative simplicity of olefin metathesis. The most common catalysts in the Ruthenium-catalyzed olefin metathesis are Grubbs’ catalysts (first and second generation) and Hoveyda–Grubbs’ catalysts (first and second generations). The mechanism starts with the stable catalyst (16e – ) initiation cycle, which theoretically can go either via a dissociative pathway (14e – ) , or an associative pathway (18e – ) , or an interchange pathway. After the loss of Styrene, the main catalytic cycle continues with the 'active' catalyst. The mechanism is rather complex and varies significantly depending on the substrate and catalyst. Wheel of olefin meta...