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The pKa of KHP is 5.4, so its pH buffering range would be 4.4 to 6.4; however, due to the presence of the second acidic group that bears the potassium ion, the first pKa also contributes to the buffering range well below pH 4.0, which is why KHP is a good choice for use as a reference standard for pH 4.00.
The monopotassium salt, potassium hydrogen phthalate is a standard acid in analytical chemistry. Typically phthalate esters are prepared from the widely available phthalic anhydride. Reduction of phthalic acid with sodium amalgam in the presence of water gives the 1,3-cyclohexadiene derivative. [13]
Potassium bromate (KBrO 3) for standardisation of sodium thiosulfate solutions; Potassium hydrogen phthalate (usually called KHP) for standardisation of aqueous base and perchloric acid in acetic acid solutions; Sodium carbonate for standardisation of aqueous acids: hydrochloric, sulfuric acid and nitric acid solutions (but not acetic acid)
The standard state of a material (pure substance, mixture or solution) is a reference point used to calculate its properties under different conditions.A degree sign (°) or a superscript Plimsoll symbol (⦵) is used to designate a thermodynamic quantity in the standard state, such as change in enthalpy (ΔH°), change in entropy (ΔS°), or change in Gibbs free energy (ΔG°).
Where W KHP is the mass (g) of potassium hydrogen phthalate (KHP) in 50 ml of KHP standard solution, V eq is the volume of titrant (ml) consumed by 50 ml KHP standard solution at the equivalent point, 204.23 g/mol is the molecular weight of KHP.
Phthalates (US: / ˈ θ æ l eɪ t s / UK: / ˈ θ ɑː l eɪ t s ˌ ˈ f θ æ l ɪ t s / [1] [2]), or phthalate esters, are esters of phthalic acid. They are mainly used as plasticizers, i.e., substances added to plastics to increase their flexibility, transparency, durability, and longevity. They are used primarily to soften polyvinyl ...
All data as presented in these tables is for materials in their standard state, which is at 25 °C and 100 kPa by definition. If values are given for other conditions, this is explicitly indicated. If values are given for other conditions, this is explicitly indicated.
It is manufactured by treating an aqueous solution of potassium carbonate or potassium hydroxide with carbon dioxide: [1] K 2 CO 3 + CO 2 + H 2 O → 2 KHCO 3. Decomposition of the bicarbonate occurs between 100 and 120 °C (212 and 248 °F): 2 KHCO 3 → K 2 CO 3 + CO 2 + H 2 O. This reaction is employed to prepare high purity potassium carbonate.