Podcast
Questions and Answers
What is the purpose of using excess formaldehyde in the estimation of glycine purity?
What is the purpose of using excess formaldehyde in the estimation of glycine purity?
- To prevent the formation of zwitterions
- To block the amino group by forming methylene glycine (correct)
- To enhance the reaction with NaOH
- To neutralize the glycine solution
Why is it important for the formaldehyde solution and glycine solutes to be brought to the same pH before mixing?
Why is it important for the formaldehyde solution and glycine solutes to be brought to the same pH before mixing?
- To maintain stability of the cation formed
- To prevent zwitterion formation
- To avoid interference with formic acid
- To ensure optimal reaction conditions (correct)
Why can't amino acids like glycine be estimated by direct titration with standard alkali solution?
Why can't amino acids like glycine be estimated by direct titration with standard alkali solution?
- Neutralization of amino acids by alkali solution
- Formation of unstable compounds with alkali solution
- Inability of amino acids to react with alkali solution
- Amino group interference at the end point (correct)
What is the role of NaOH in the estimation process of glycine purity?
What is the role of NaOH in the estimation process of glycine purity?
What is the state of glycine in aqueous solution before reacting with formaldehyde and NaOH?
What is the state of glycine in aqueous solution before reacting with formaldehyde and NaOH?
What is the purpose of using excess formaldehyde in the estimation of glycine purity?
What is the purpose of using excess formaldehyde in the estimation of glycine purity?
What is the role of NaOH in the estimation process of glycine purity?
What is the role of NaOH in the estimation process of glycine purity?
Why can't amino acids like glycine be estimated by direct titration with standard alkali solution?
Why can't amino acids like glycine be estimated by direct titration with standard alkali solution?
What is the state of glycine in aqueous solution before reacting with formaldehyde and NaOH?
What is the state of glycine in aqueous solution before reacting with formaldehyde and NaOH?
Why is it important for the formaldehyde solution and glycine solutes to be brought to the same pH before mixing?
Why is it important for the formaldehyde solution and glycine solutes to be brought to the same pH before mixing?
Flashcards
Formaldehyde's role in glycine purity
Formaldehyde's role in glycine purity
Blocks the amino group, forming methylene glycine, enabling accurate estimation.
Equal pH for formaldehyde and glycine
Equal pH for formaldehyde and glycine
Ensures optimal reaction conditions, preventing unwanted reactions during titration.
Direct titration of amino acids
Direct titration of amino acids
Not possible due to interference of the amino group at the endpoint of the reaction.
NaOH's role in glycine estimation
NaOH's role in glycine estimation
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Glycine's aqueous state (before reaction)
Glycine's aqueous state (before reaction)
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Glycine's role in zwitterion form
Glycine's role in zwitterion form
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Formaldehyde excess purpose
Formaldehyde excess purpose
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NaOH's effect on glycine
NaOH's effect on glycine
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Amino group interference
Amino group interference
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Zwitterion and reaction
Zwitterion and reaction
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Study Notes
Estimation of Glycine Purity
- Excess formaldehyde is used to ensure complete reaction with glycine, allowing for accurate estimation of glycine purity.
- The formaldehyde solution and glycine solutes must be brought to the same pH before mixing to prevent uneven reaction rates and ensure accurate results.
Titration of Amino Acids
- Amino acids like glycine cannot be estimated by direct titration with standard alkali solution because they do not react with alkali in a straightforward manner.
Role of NaOH
- NaOH is used to convert glycine into its anionic form, allowing it to react with formaldehyde and facilitating the estimation process.
State of Glycine in Aqueous Solution
- In aqueous solution, glycine exists in its zwitterionic form, which must be converted to its anionic form by NaOH before reacting with formaldehyde.
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Description
Learn about the estimation of amino acids, such as glycine, using Sorenson's Formal titration method. This quiz covers the identification of percentage purity of a glycine sample and the determination of the amount of amino acid present in a given solution.
