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.
because in the preparation of hydrogen gas ......granulated zinc is used n which is the purest form of zinc. if granulated zinc reacts with dilute sulphuric acid .....there , a displacement reaction takes place but the purest form of zinc don't react with concentrated sulphuric acid ..... . i.e ....there will be no displacement reaction ....so hydrogen gas will not be formed
It is because it absorbs moisture from air and therefore doesn't meet the criteria for a primary standard.
HCl is not used as a primary standard
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.
HCl, hydrochloric acid, is the primary standard used to titrate against potassium hydroxide.
Sodium hydoxide cannot be used as a primary standard because of its hygroscopic properties as a solid. Because it is so prone to absorbing water, it is impossible to accurately measure the mass of a solid sample, so instead it must be put into solution and tirated with a known acidic solution, such as HCl. This makes it a secondary standard as opposed to a primary standard. By. Kuatsienu Divine
solution containig (3.3)gm na2co3 .h2o in (15ml)
HCl is not used as a primary standard
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
HCl, hydrochloric acid, is the primary standard used to titrate against potassium hydroxide.
Sodium hydoxide cannot be used as a primary standard because of its hygroscopic properties as a solid. Because it is so prone to absorbing water, it is impossible to accurately measure the mass of a solid sample, so instead it must be put into solution and tirated with a known acidic solution, such as HCl. This makes it a secondary standard as opposed to a primary standard. By. Kuatsienu Divine
solution containig (3.3)gm na2co3 .h2o in (15ml)
sodium hydroxide is a secondary standard because it absorb the moisture from the air and its concentration will change
The usual primary standard for acid-base titration is sulfuric acid. Nitric acid tends to lose NO2 by volatilization and HCl is also more volatile.
The chemical formula (not symbol) of hydrogen chloride is HCl; for a diluted solution you can use "HCl dil." but this isn't a standard formula.
HCl is liquid at standard temperature and pressure
we use primary standard apparatus in chemistry lab to find accurate resultthe examples of primary standard apparatus arepippetteburreteVolumetric Flask
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.