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Carbocations: Factors affecting their Stability

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A carbocation is a species where a carbon atom bonds to three carbon atoms and has a positive charge. Carbocations are electron deficient species and therefore very reactive and unstable . Anything which donates electron density to the electron-deficient center will help to stabilize them. Factors that stabilize them are the following:  Neighboring carbon atoms (inductive effect) Neighboring carbon-carbon multiple bonds (resonance effect) Neighboring atoms with lone pairs (resonance effect) How carbocations are stabilized by neighboring carbons atoms? The stability of carbocations decreases as the number of carbons attached to the C+ decreases. That means that tertiary carbocations are more stable than secondary that in turn are more stable than primary (Fig. 1). Fig. 1: Carbocation stability increases as methyl substitution increases around the electron deficient carbon C+. The methyl groups (-CH 3 ) are electron donating and therefore stabilize the positive charge (inductive ...
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Analytical Chemistry - Calibration

Analytical Chemistry - Calibration Home > Analytical Chemistry > Calibration CALIBRATION What is calibration? Calibrated instruments|Analytical Chemistry Calibrating a pH meter using buffers Quantitative Analysis by Atomic Absorption Performance Verification of Analytical Balances according to ISO/IEC 17025 Calibration and Outliers - Statistical Analysis Calibration of an instrument in Analytical Chemistry is the operation that determines the functional relationship between measured values (signal intensities S at certain signal positions zi) and analytical quantities characterizing types of analytes qi and their amount ( content , concentration ) n. Calibration includes the selection of the model (its functional form), the estimation of the model parameters as well as the errors, and their validation. During calibration , the in...
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Self-ionization of water - Autoionization of water - The ion product of water (kw)

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Self-ionization of water - Autoionization of water - The ion product of water (kw) Home > Weak Acids and Bases – Calculate the pH of a weak acid (a general equation) > Solving Weak Acid and Weak Base pH problems > Weak Acid Weak Base pH calculation solved example > Weak Acid Weak Base pH calculation solved example > Cubic Equation Calculator for Weak Acid-Base Equilibria > Polyprotic Acids / pH Calculation > Self-ionization of water - Autoionization of water - The ion product of water (kw) Self-ionization of water - Autoionization of water - The ion product of water (kw) A water molecule can act as an acid and as a base according to: In the above reaction – autoionization of water - one water molecule acts as an acid donating a proton to the other water molecule that acts as a base – proton acceptor. From the equation we see that for every hydronium ion H 3 O + that is formed a hydroxyl ion...
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