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Assumption 2. The self-ionization of water can be ignored. This assumption is not, strictly speaking, valid with pH values close to 7, half the value of pK w, the constant for self-ionization of water. In this case the mass-balance equation for hydrogen should be extended to take account of the self-ionization of water.
For example, the pH of a 0.01 in moles per litreM solution of hydrochloric acid (HCl) is equal to 2 (pH = −log 10 (0.01)), while the pOH of a 0.01 M solution of sodium hydroxide (NaOH) is equal to 2 (pOH = −log 10 (0.01)), which corresponds to a pH of about 12.
Pauling's second rule is that the value of the first pK a for acids of the formula XO m (OH) n depends primarily on the number of oxo groups m, and is approximately independent of the number of hydroxy groups n, and also of the central atom X. Approximate values of pK a are 8 for m = 0, 2 for m = 1, −3 for m = 2 and < −10 for m = 3. [28]
The Charlot equation, named after Gaston Charlot, is used in analytical chemistry to relate the hydrogen ion concentration, and therefore the pH, with the formal analytical concentration of an acid and its conjugate base. It can be used for computing the pH of buffer solutions when the approximations of the Henderson–Hasselbalch equation ...
In chemistry, acid value (AV, acid number, neutralization number or acidity) is a number used to quantify the acidity of a given chemical substance.It is the quantity of base (usually potassium hydroxide (KOH)), expressed as milligrams of KOH required to neutralize the acidic constituents in 1 gram of a sample.
The Pt anode generates I 2 from the KI when current is provided through the electric circuit. The net reaction as shown below is oxidation of SO 2 by I 2. One mole of I 2 is consumed for each mole of H 2 O. In other words, 2 moles of electrons are consumed per mole of water. 2 I − → I 2 + 2 e − B·I 2 + B·SO 2 + B + H 2 O → 2 BH + I ...
Addition (or removal) of CO 2 to a solution does not change its alkalinity, since the net reaction produces the same number of equivalents of positively contributing species (H +) as negative contributing species (HCO − 3 and/or CO 2− 3). Adding CO 2 to the solution lowers its pH, but does not affect alkalinity. At all pH values: CO 2 + H 2 ...
Figure 2 gives an example; in this example, the two x-intercepts differ by about 0.2 mL but this is a small discrepancy, given the large equivalence volume (0.5% error). Similar equations can be written for the titration of a weak base by strong acid (Gran, 1952; Harris, 1998).