Why is it necessary to prepare a secondary standard solution? (1 Viewer)

[Dreamerish*~]

edit: never mind '-_-. i had a mind block. however i'm keeping this thread here if anyone wants to offer an explanation better than my own.

i'm talking about using HCl to standardise a NaOH solution. you can't make a NaOH solution because dry NaOH absorbs moisture from the atmosphere, therefore making calculations inaccurate. therefore it needs to be standardised by a primary standard - HCl.

am i wrong?

 

[funking_you]

HCl is NOT a primary standard. It cannot be obtained as a pure & stable solid.
HCl normally exists as a gas, HCl(g) , and when it is dissolve in water, it forms an acidic solutions, HCl(aq).
A commonly used acidic primary standard is oxalic acid.

 

[Dreamerish*~]

the question is:

"... standardized the sodium hydroxide solution using standard hydrochloric acid and then used sodium hydroxide solution to determine the concentration of the acetic acid solution... Explain the purpose of the first titration performed."

how would i explain that?

 

[thunderdax]

The purpose is to find the concentration of the sodium hydroxide solution which you can't prepare a primary standard of. You then need this concentration to find the conc. of the acetic acid.

 

[xiao1985]

@ dreamish: HCl is not a primary standard as chem coach said... however you might have standardised it before hand using some other primary standard...

and since u have already standardised it, u can use it to standardise NaOH...

 

[Dreamerish*~]

thank you all

muchly appreciated.