1. what should be the limiting reagent in this reaction? the theoretical stoichiometric ratio between reactants benzaldehyde and acetone is 2: 1. we used more than that in this lab. why is this ratio (or more) necessary?
2. why do you wash the reaction mixture twice with water?
3. what is the minor product of this reaction? draw its structure and name it.
4. in the ir spectrum of pure dibenzalacetone, a peak appears at 1639 cm-1, which you might have predicted at 1710 cm-1. identify the functional group and explain why it appears in a different region than expected.

answer; talc and gypsum;

answer : third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol

explanation :

let us write down the given equations

equation 1 :

equation 2 :

equation 3 :

let us use hess's law to find out which 2 equations can be added to get the third equation.

let us reverse equation 2 and multiply it by 2. the new equation that we get is,

equation 4 :

let us add equation 1 & 4

the above equation is similar to equation 3 but has different value for dhrxn.

therefore third trial had the contaminated sample and the correct value for dhrxn should be 1000 kj/mol