10 Questions
What is the purpose of using excess formaldehyde in the estimation of glycine purity?
To block the amino group by forming methylene glycine
Why is it important for the formaldehyde solution and glycine solutes to be brought to the same pH before mixing?
To ensure optimal reaction conditions
Why can't amino acids like glycine be estimated by direct titration with standard alkali solution?
Amino group interference at the end point
What is the role of NaOH in the estimation process of glycine purity?
To convert glycine into a form that can react with formaldehyde
What is the state of glycine in aqueous solution before reacting with formaldehyde and NaOH?
"Zwitterion"
What is the purpose of using excess formaldehyde in the estimation of glycine purity?
To block the amino group by forming methylene glycine
What is the role of NaOH in the estimation process of glycine purity?
To convert glycine into a stable cation
Why can't amino acids like glycine be estimated by direct titration with standard alkali solution?
Amino group interference at the end point
What is the state of glycine in aqueous solution before reacting with formaldehyde and NaOH?
"Zwitterion" incapable of reacting with formaldehyde
Why is it important for the formaldehyde solution and glycine solutes to be brought to the same pH before mixing?
To prevent undesirable side reactions during titration
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.
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.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
