2 Formalin + 2 Benedict's Reagent + 4 OH -> 2 +4 + Cu2O + H2O 2. Differentiate the following pair of compounds. Indicate the reagent and the expected visible results.
a.
and
To differentiate these compounds, the Iodoform test is needed. The compound that will give the positive result is 2-hexanone because Iodoform test will react with methyl ketones. The visible result is production of yellow precipitate.
b.
and To differentiate these compounds, the Schiff's test is needed. This test is used to differentiate aldehydes from ketones. It returns a purple color if the compound is an aldehyde.
c. and d. 2-hexanone and 3-pentanone As with letter a, the test to be used is the Iodoform test which will give yellow precipitate in methyl ketones, in this case 2-hexanone.
3. Discuss briefly the effect of acid concentration on the rate of addition or formation of precipitate with 2,4-DNPH in part E. The addition of 2,4-DNPH needs optimum pH to proceed. Any lower pH will make 2,4-DNPH not + nucleophilic enough to donate a lone pair to Carbon and any higher pH will lessen the H ions to make the reaction proceed. Sources : http://www.harpercollege.edu/tm-ps/chm/100/dgodambe/thedisk/qual/dnp.htm
