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What are the primary and secondary standards used in acid base titration?
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Michael Davison
What are the primary and secondary standards used in acid base titration?
I can tell you what a primary standard is, but I can’t tell you what the primary standard is without the experimental procedure in front of me.
A primary standard is one that is prepared to a known concentration. Often this is a dilution from a “concentrated” (saturated, in truth) solution. More rarely, it is prepared from a solid—such as potassium hydrogen phthalate, or KHP—that doesn’t readily absorb water from the atmosphere.
A secondary standard, by contrast, is one that you produced to an approximate concentration, then titrated with a primary standard to find the exact concentration. Sodium hydroxide is generally a secondary standard, for instance, since saturated solutions absorb carbon dioxide from the air over time and lose their basicity, so they usually get prepared fresh from solid pellets. But those solid pellets, unlike KHP, do absorb water from the atmosphere fairly readily, so their mass is only mostly sodium hydroxide and the actual concentration is going to be lower than the mass would indicate. But not by a consistent percentage, thus the need for a titration to determine the actual concentration.
I can tell you what a primary standard is, but I can’t tell you what the primary standard is without the experimental procedure in front of me.
A primary standard is one that is prepared to a known concentration. Often this is a dilution from a “concentrated” (saturated, in truth) solution. More rarely, it is prepared from a solid—such as potassium hydrogen phthalate, or KHP—that doesn’t readily absorb water from the atmosphere.
A secondary standard, by contrast, is one that you produced to an approximate concentration, then titrated with a primary standard to find the exact concentration. Sodium hydroxide is generally a secondary standard, for instance, since saturated solutions absorb carbon dioxide from the air over time and lose their basicity, so they usually get prepared fresh from solid pellets. But those solid pellets, unlike KHP, do absorb water from the atmosphere fairly readily, so their mass is only mostly sodium hydroxide and the actual concentration is going to be lower than the mass would indicate. But not by a consistent percentage, thus the need for a titration to determine the actual concentration.
Primary is an acid substance that is weighable with a high molecular weight and non hydroscopic. The use of sodium acid phthalate is considered the primary standard for this reason. Once the base is ‘standardized, usually NaOH, the strong acid, like HCl or H2SO4, is then standardized against the base…
Primary is an acid substance that is weighable with a high molecular weight and non hydroscopic. The use of sodium acid phthalate is considered the primary standard for this reason. Once the base is ‘standardized, usually NaOH, the strong acid, like HCl or H2SO4, is then standardized against the base…
I can tell you what a primary standard is, but I can’t tell you what the primary standard is without the experimental procedure in front of me.
A primary standard is one that is prepared to a known concentration. Often this is a dilution from a “concentrated” (saturated, in truth) solution. More rarely, it is prepared from a solid—such as potassium hydrogen phthalate, or KHP—that doesn’t readily absorb water from the atmosphere.
A secondary standard, by contrast, is one that you produced to an approximate concentration, then titrated with a primary standard to find the exact concentration. Sodium hydroxide is generally a secondary standard, for instance, since saturated solutions absorb carbon dioxide from the air over time and lose their basicity, so they usually get prepared fresh from solid pellets. But those solid pellets, unlike KHP, do absorb water from the atmosphere fairly readily, so their mass is only mostly sodium hydroxide and the actual concentration is going to be lower than the mass would indicate. But not by a consistent percentage, thus the need for a titration to determine the actual concentration.
I can tell you what a primary standard is, but I can’t tell you what the primary standard is without the experimental procedure in front of me.
A primary standard is one that is prepared to a known concentration. Often this is a dilution from a “concentrated” (saturated, in truth) solution. More rarely, it is prepared from a solid—such as potassium hydrogen phthalate, or KHP—that doesn’t readily absorb water from the atmosphere.
A secondary standard, by contrast, is one that you produced to an approximate concentration, then titrated with a primary standard to find the exact concentration. Sodium hydroxide is generally a secondary standard, for instance, since saturated solutions absorb carbon dioxide from the air over time and lose their basicity, so they usually get prepared fresh from solid pellets. But those solid pellets, unlike KHP, do absorb water from the atmosphere fairly readily, so their mass is only mostly sodium hydroxide and the actual concentration is going to be lower than the mass would indicate. But not by a consistent percentage, thus the need for a titration to determine the actual concentration.
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Primary is an acid substance that is weighable with a high molecular weight and non hydroscopic. The use of sodium acid phthalate is considered the primary standard for this reason. Once the base is ‘standardized, usually NaOH, the strong acid, like HCl or H2SO4, is then standardized against the base…
Primary is an acid substance that is weighable with a high molecular weight and non hydroscopic. The use of sodium acid phthalate is considered the primary standard for this reason. Once the base is ‘standardized, usually NaOH, the strong acid, like HCl or H2SO4, is then standardized against the base…
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