Question

Difference between formal titration and formol titration

Answer 1

Answer:

the principle of this method is that formaldehyde make blocking of amino group of amino acid so amino acid become more acidic (monomethylol and dimethylol derivative of amino acid) and titrated with base(0.1M sodium hydroxide).

method

1-first neutralization of 10 % of formaldehyde by taking in conical flask 5 ml formaldehyde and 2 drops of ph.ph (0.1 g in 50 ml dist.H2O) then titrate against 0.1M sodium hydroxide till faint pink color and leave beside

2- 12.5 ml of amino acid ( of unknown conc.) and 2 drops of ph.ph and titrate against 0.1M sodium hydroxide till faint pink and this step for removal of one protn from amino group of amino acid present in soln. in form of zwitter ion

then mix 1 on 2 giving colorless soln. titrate it against 0.1M sodium hydroxide till faint pink color and record volume of sodium hydroxide used in titration