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The genetic code is a set of rules used by living cells to translate information encoded within genetic material ( DNA/RNA  sequences of nucleotide  triplets/codons ) into proteins. Translation is accomplished by ribosome, which links proteinogenic amino acids in an order specified by the messenger  RNA (mRNA) , using the transfer  RNA (tRNA)  molecules to carry amino acids and to read the  mRNA  triplets/codons at a time. Question: What will be the sequence of mRNA produced by the following stretch of DNA ? 3’ATGCATGCATGCATG5’ template strand 5’TACGTACGTACGTAC3’ coding strand Solution: Click/tap to enlarge the image Bombastic biochemistry ❓ Let Chemaficionado know in the comments below or at mychemistryhomework@gmail.com ❗ Reference: Wikipedia Contributors.  Genetic code . Wikipedia.

Qualitative organic analysis  focuses on the development, validation and application of methods to identify unknown compounds, sometimes in a mixture or a solution. With the advent of sophisticated analytical instruments, the identification (and quantification and purification) of organics has become easier than ever; however, not all labs have a direct access to these instruments, which, more often than not, may cost you a fortune. Glassware-based wet lab reactions may still help one identify an organic compound. Question: Identify ( A ) on the following image: Click/tap to enlarge the image Solution infographic: Click/tap to enlarge the image MF = Molecular formula, IHD = Index of hydrogen deficiency or degree of unsaturation ( DU/DoU ) or double bond equivalent ( DBE ) These questions are often given in the exams with descriptions. You should make a summary like the question above for a problem-solving approach. Quibbling about qualitative analysis ❓ Let Chemaficionado know ...

The Grignard reagent is synthetically versatile as the organomagnesium compound can react with a variety of electrophiles . The mechanism is not well-understood and most likely involves a single electron transfer ( SET ). The reactions require dry solvents such as THF ( Tetrahydrofuran ). Grignard reagents cannot be prepared using molecules having acidic hydrogens or electrophilic centers. Carbon dioxide or conjugated systems also react with Grignard reagents. Wheel of no Grignard reactions: Click/tap to enlarge the image For a whopping wheel of Grignard reactions, click HERE . What other wheel(s) 🎡 of organic reactions would you like to see❓ Questions ❓ Let Chemaficionado know in the comments below or at mychemistryhomework@gmail.com ❗ References: (1)      Chouhan, M. S.  Advanced Problems in Organic Chemistry for JEE , 11th Ed. (2)      Ncert.  Chemistry : Textbook for Class XII - Part.II ; National Council Of Educational Research And Tr...

Qualitative organic analysis  focuses on the development, validation and application of methods to identify unknown compounds, sometimes in a mixture or a solution. With the advent of sophisticated analytical instruments, the identification (and quantification and purification) of organics has become easier than ever; however, not all labs have a direct access to these instruments, which, more often than not, may cost you a fortune. Glassware-based wet lab reactions may still help one identify an organic compound. Question: Identify ( A ) on the following image: Click/tap to enlarge the image Solution infographic: Click/tap to enlarge the image MF = Molecular formula, IHD = Index of hydrogen deficiency or degree of unsaturation ( DU/DoU ) or double bond equivalent ( DBE ) Quantitative analysis of active hydrogens in a chemical compound by adding Methylmagnesium iodide in Pentyl ether to the solution of analyte and quantitatively determining the volume of Methane gas formed uses Z...

Solubility equilibrium  is a type of dynamic equilibrium that exists when a solid chemical compound is in chemical equilibrium with a solution of that compound. The solid may dissolve unchanged, with dissociation, or with chemical reaction with another component of the solution,  viz. , acid, base or salt. Each solubility equilibrium is characterized by a temperature-dependent solubility product which functions like an equilibrium constant. Question: Equal volumes of 0.002 M solutions of Sodium iodate and Copper(II) chlorate are mixed together. Will it lead to precipitation of Copper(II) iodate? (For Copper(II) iodate, K sp = 7.4 × 10 –8 ). Solution: Click/tap to enlarge the image Nemesis on no precipitation❓ Let Chemaficionado know in the comments below or at mychemistryhomework@gmail.com ❗ References: (1)      Wikipedia Contributors.  Solubility equilibrium . Wikipedia. https://en.wikipedia.org/wiki/Solubility_equilibrium. ‌ (2)      ...

The Grignard reagent is synthetically versatile as the organomagnesium compound can react with a variety of electrophiles . The mechanism is not well-understood and most likely involves a single electron transfer ( SET ). The substrate must not have any acidic groups. The reactions require dry solvents such as THF ( Tetrahydrofuran ). Question: Predict the major product(s) of the following reaction: Click/tap to enlarge the image Solution infographic: Click/tap to enlarge the image For a whopping wheel of Grignard reactions, click HERE . Grumpy about Grignard reactions❓ Let Chemaficionado know in the comments below or at mychemistryhomework@gmail.com ❗ NOTE: Post updated since published References: (1)      Chouhan, M. S.  Advanced Problems in Organic Chemistry for JEE , 11th Ed. (2)      Ncert.  Chemistry : Textbook for Class XII - Part.II ; National Council Of Educational Research And Training: New Delhi.

The second law of thermodynamics establishes the concept of entropy as a physical property of a thermodynamic system. In a natural thermodynamic process, the sum of the entropies of the interacting thermodynamic systems NEVER decreases. The term ‘spontaneous’ has historically been used to describe processes for which the change in Gibbs free energy in the standard state, ΔG Ѳ < 0 . The phrase ‘thermodynamically favored’ is preferred instead so that common misunderstandings equating ’spontaneous’ with ‘suddenly’ or ‘without cause’ can be avoided. Question: As a sample of KNO₃(s) is stirred into water at 25°C , the compound dissolves endothermically. How would you explain why the process is thermodynamically favorable at 25°C? Solution: Click/tap to enlarge the image ΔH Ѳ = Standard change in enthalpy, T = Absolute temperature, ΔS Ѳ = Standard change in entropy Tug-of-war with thermodynamics❓ Let Chemaficionado know in the comments below or at mychemistryhomework@g...

A cyanohydrin or hydroxynitrile is a functional group in organic compounds in which a cyano and a hydroxy group are attached to the same carbon atom. Cyanohydrins are commercially important precursors to carboxylic acids and some amino acids and can be formed by the cyanohydrin reaction, which involves treating a ketone or an aldehyde with Hydrogen cyanide ( HCN ) in the presence of excess amounts of Sodium cyanide ( NaCN ) as a catalyst. The catalyst can be a (stronger) base or an enzyme, too. Due to hazards with HCN , other less dangerous cyanation reagents are used nowadays. Wheel of cyanohydrins: Click/tap to enlarge the image What other wheel(s) 🎡 of organic reactions would you like to see❓ Questions ❓ Let Chemaficionado know in the comments below or at mychemistryhomework@gmail.com ❗ Reference: Wikipedia Contributors.  Cyanohydrin . Wikipedia.

Chemical kinetics aka reaction kinetics is concerned with understanding the rates of chemical reactions. If one of the plots in the following table shows linearity (indicated by a constant slope), the order of the reaction w.r.t.  the substrate ( S ) is the corresponding one. Plot Order [S] (mol L ─1 ) versus time ( s ) Zero ln [S]  versus   time ( s ) First 1/[S] (L mol ─1 )  versus   time ( s ) Second Question: The data from a study of the decomposition of NO₂(g) to form NO(g) & O₂(g) are given in the table below. What is the order of the reaction w.r.t. NO₂(g) that is consistent with the data? Time ( s ) [NO 2 ] (mol L ─1 ) ln [NO 2 ] 1/[NO 2 ] (L mol ─1 ) 0 0.500 ─ 0.693 2.00 100 0.364 ─ 1.01 2.75 200 0.286 ─ ...

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: 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! Sensible substitution❓ Let Chemaficionado know in the comments below or at mychemistryhomework@gmail.com ❗ References: (1)      Ncert.  ...

Amine alkylation is an organic reaction typically between an alkyl halide (or an alcohol) and ammonia or an amine. The reaction is poorly selective, often requiring separation of the products. Question: Predict the product(s) of the following reactions: Click/tap to enlarge the image Solution infographic: Click/tap to enlarge the image DMA = Dimethylaniline Industrially, most alkylations are typically done using alcohols, not alkyl halides as alcohols are less expensive than alkyl halides and their alkylation does not produce salts, the disposal of which can be challenging. Astonishing alkylation❓ Let Chemaficionado know in the comments below or at mychemistryhomework@gmail.com ❗ References: (1)      Ncert.  Chemistry : Textbook for Class XII - Part.II ; National Council Of Educational Research And Training: New Delhi. (2)      Brown, C.; Ford, M.  Higher Level Chemistry , 2nd ed.; Pearson Education: Harlow, Essex, 2014. (3)   ...

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 . Let's keep in mind that the presence of an activating group on the ring may complicate nitration. Question: Predict the major product(s) of the following reactions: Click/tap to enlarge the image Solution infographic: Click/tap to enlarge the image Eerie EAS chemistry❓ 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)      Brown, C.; Ford, M.  Higher Level Chemistry , 2nd ed.; Pearson Education: Harlow, Essex, 2014. ‌(3)     Electrophilic aromatic directing gro...