KHP (potassium hydrogen phthalate) is available extremely pure (which is always good for a primary standard) and gives a very sharp end-point especially with Crystal Violet Indicator
H2SO4 and HCl
KHP a is good primary standard for several reasons. It's rather cheap, the purity level is high, it's water soluble, and best of all, it's chemically stable.
The reasons KHP is used as a primary standard are as follows: (1) It is not hydroscopic, (2) it has a high molecular weight, so a reasonable amount to titrate can be easily weighed, and (3) it is stable at temperatures over 100°C so that any water may be driven off by heating.
It is a solution of known concentration. In acid base titrations we used KHP as the acid standard. We weighed it to 0.1 mg and made the solution up to a certain volume in a volumetric flask. We then standardized the base by titration. KHP was thus the primary standard and NaOH the secondary std.
Perchloric acid is a strong acid, whereas potassium hydrogen phthalate (KHP) is a weak acid. Therefore, perchloric acid will protonate KHP to form phthalic acid. In other words, even though both are considered acids, KHP is more basic than perchloric acid (when you compare their pKa or Ka, the true measure of acid strength). I'm not entirely sure what you mean by "standardized" however. Do you mean doing a titration? Often a solution of KHP is used to calibrate a pH meter because it's pH in solution is very stable. I would be surprised if a titration was done with perchloric acid and KHP however, but I'm not sure what else you could mean by asking why an acid is standardized using KHP. KHP is the primary standard used for the standarization of perchloric acid, usually 0.1M HCLO4 in concentration. It is the recommended primary standard in the pharmaceutical industry for analytical testing using perchloric acid for non-aqueous titration determinations. The protonation of KHP to phthalic acid when reacted with perchloric acid can be determined stoichiometrically. Using a dried KHP standard of known purity allows the determination of HCLO4.
Primary standard is a chemical entity available with highest purity and stability with high molecular weight. e.g. KHP, NaCl, Calcium salt used in standardisation of volumetric solution. Secondary standards are compounds used in analysis after evaluation against primary standards. e.g.- NaOH VS, Sodium thiosulphate VS
Potassium acid phthalate is a common primary standard used to standardize bases. Obviously, it would depend upon how much NaCl was present, but the end result will be to reduce the amount of available H+ for the mass of KHP-NaCl mixture. That would cause you to understate the concentration of the base.
It has lower molecular wt, it is hygroscopic and has lower purity so it is not used as the primary standard
HCl is not used as a primary standard
It is used as a standard but not as a primary standard. It tends over time to precipitate sulfur. Na2S2O3 = Na2SO3 + S
HCl, hydrochloric acid, is the primary standard used to titrate against potassium hydroxide.
KHP + NaOH = H2O + NaKP or KHP + NaOH = H2O + KNaP or KHP + NaOH = H2O + K + NaP
It is primary standard is a substance that has a known high digree of purity ,reatively large molar mass ,is nonhygroscopic and reacts in a predic table way.
Either full synthetic or standard primary oil.
In order for a substance to be a primary standard it must be able to dissolve in water. Since iodine is unable to do this it cannot be used as a primary standard
Primary standard can be defined in metrology, as a standard that is accurate enough that it is not calibrated by or subordinate to the other standards. Primary standards are used to calibrate other standards.
It is because it absorbs moisture from air and therefore doesn't meet the criteria for a primary standard.
KHC8H4O4(aq) + NaOH(aq) --> KNaC8H4O4(aq) + H2O(l). The molar mass of KHP is approximately 204.22 g/mol. 1.54g of KHP is equivalent to 0.00754 mol of KHP. 1 mole of NaOH reacts per mole of KHP, so .00754 mol of NaOH are needed.
molar mass of KHP is 204.2g/mole. the formula for KHP is C8H5O4K therefore, (12.01*8)+(1.008*5)+(16*4)+39.1 = 204.2g/mol
No. Chemical compounds have to fulfill a number of requirements before they can be classified and used as a primary standard: A primary standard in chemistry is a reliable, readily quantified substance. Features of a primary standard include: 1. High purity 2. Stability (low reactivity) 3. Low hygroscopicity and efflorescence 4. High solubility (if used in titration) 5. High equivalent weight 6. Non-toxicity 7. Ready and cheap availability Edta and particularly the sodium salts of EDTA which are frequently used do not fulfill the first requirement. Therefore the solution of EDTA has to be standardised against a known and accepted primary standard.
Yes, sodium Chloride solution is used as a primary standard.
a primary standard should essentially available in pure form , stable towards light and heat and react in a stoichiometric proportion. HCl is a gas which is dissolved in water to form the solution the concentration expressed is very approximate so its not a primary standard. NaOH cannot be weighed in open air because it is highly hygroscopic. FeSO4 under goes aerial oxidation .so all these are not used as primary standards . but they can be used as secondary standards as the solutions have to be titrated each and every day against a primary standard.
Potassium Hydroganphthalate is used
KHP + KOH = KKP + H2O