Question

1.explain why it is more efficient to make several extraction using small portions rather than one extraction.
2.defined drying agent intensity
3.defined drying agent capacity
4.what is the upper layer in each mixed solvents
a-water and benzene
b-water and ether
c-water and carbon tetrachloride
5.write an equation for this reaction of benzoic acid with aqueous sodium bicarbonate

Answer 1

Q1.

beacaus the mass transfer coefficient is maximized when concentrations are larger in difference...

mathematically, this can be proved:

qn = [1/(KdVo+1]^n

as n increases, the total amount (qn) of species is recovered

Q2.

Drying agent intensity: It measure the efficiency of intensity that is the degree of dryness attained. Therefore, the higher intensity, the more dry the product will be, i.e. less humnidity

Q3.

defined drying agent capacity --> It is the capacity refers to the maximum numbers of moles of water that the drying agent can bind. It is a direct measure which can be related to stoichiometric ratios

Q4.

upperlayer will be always those with LEAST density, i.e. less mass per unit volume

a) water + benzene, since water is heavier/more dense, expect benzene in upper layer

b) similar as before

c) in this case, CCl4 is heavier than water, so expect water in the top

Q5.

benzoic acid + sodium bicarbonate

2C7H6O2(aq) + Na2CO3(aq) --> CO2(g) + H2O(l) + Na2C7H4O2(aq)