Activity No. 3

Question 1

the 2 quantitative analyses done in this experiment

Answer 1

neutralization equivalent
saponification value

Question 2

neutralization equivalent and saponification value are based on the chemistry of what functional groups

Answer 2

carboxylic acid
ester

Question 3

what are identified thru the -COOH group

Answer 3

carboxylic acids and fatty acids

Question 4

once characterized as carboxylic acid and fatty acid, the ________ of the unknown can be verified thru its _______

Answer 4

structural proof
neutralization equivalent

Question 5

it is the equivalent weight of the acid as determined by titration with a standard base

Answer 5

Neutralization equivalent

Question 6

when can the molecular weight of the compound be calculated

Answer 6

when the number of carboxylic functional groups present per molecule is known

Question 7

an acid is said to be ______ if it has only -COOH group per molecule

Answer 7

monobasic

Question 8

if the acid is monobasic or has only -COOH group per molecule, the molecular weight is the same as its ________

Answer 8

neutralization equivalent

Question 9

an acid is called _____ if it has two -COOH groups

Answer 9

dibasic

Question 10

if an acid is dibasic, its molecular weight is ___________

Answer 10

twice the neutralization equivalent

Question 11

TRUE/FALSE
Molecular weight is a simple multiple of its neutralization equivalent

Answer 11

TRUE

Question 12

the determination of neutralization equivalent is based on the _________ to form the carboxylate of fatty acid called ______

Answer 12

reactivity of the carboxylic acid or fatty acid towards alkali
soap

Question 13

it is based on the reactivity of esters and lipids towards alkali

Answer 13

saponification equivalent

Question 14

esters and lipids (fats) ________ to give the corresponding carboxylic/fatty acid and alcohol.

Answer 14

hydrolyze

Question 15

saponification quivalent is the _______ determined by ___________

Answer 15

weight of an ester
titration with a standard base

Question 16

in technical analysis, the determination usually sought is the ___________ in of the saponification equivalent

Answer 16

saponification number

Question 17

it is the number of milligrams KOH required to saponify one gram of fat or oil

Answer 17

Saponification number

Question 18

both analyses can be performed using

Answer 18

titration

Question 19

the neutralization equivalent will be determined by

Answer 19

titrating the acid sample directly with the standard alkali

Question 20

saponification value determination will be carried out by

Answer 20

treating the ester sample w/ excess but known amount of alkali and back titrated with HCl

Question 21

a saponification reagent

Answer 21

KOH

Question 22

the saponification reagent (KOH) can be in aqueous solution if

Answer 22

the ester is water-soluble

Question 23

if the saponification reagent is not water-soluble, it will be necessary to use

Answer 23

alcoholic alkali

Question 24

in this experiment, neutralization equivalent will be performed on ______ and the saponification value will be performed on ______

Answer 24

palmitic acid
vegetable oils

Question 25

SAPONIFICATION VALUE:
first step

Answer 25

Preparation of alcoholic KOH solution. Dissolve 4g of AR KOH pellets in 125 mL of 95% ethanol. Decant for 24 hrs and filter to remove K2CO3

Question 26

SAPONIFICATION VALUE:
2nd step

Answer 26

weigh accurately 300-400 mg vegetable oil. To do this, place about 0.5 mL of the oil in a beaker. Determine its accurate weight, pour its contents into the 125 mL Erlenmeyer flask without spilling and reweigh the beaker. The difference in weight represents the accurate weight of the sample

Question 27

SAPONIFICATION VALUE:
step 3

Answer 27

to the flask containing the oil sample and another empty Erlenmeyer flask, place 12.5 mL of the alcoholic KOH solution by means of a pipette and a couple of boiling chips. one of these flasks willnact as blank. Dilute each flask w/ 5mL of 95% ethanol.

Question 28

SAPONIFICATION VALUE:
Step 4

Answer 28

fit the flasks to the reflux condensers. clamp the flask to an iron stand

Question 29

SAPONIFICATION VALUE:
Step 5

Answer 29

boil each flask gently in water bath under efficient reflux for 2 (or more) hours. swirl the mixture at frequent intervals

Question 30

SAPONIFICATION VALUE:
Step 6

Answer 30

pour 12.5 mL of distilled water down each condenser to wash its walls. remove flask from their respective condensers

Question 31

SAPONIFICATION VALUE:
Step 7

Answer 31

note the color of the solutions and then add 2 drops of phenolphthalein to each flask. Titrate the contents of each flask with standard 0.1 N HCl solution to original color

Question 32

SAPONIFICATION VALUE:
Step 8

Answer 32

calculate the saponification equivalent and saponification value. The amount of KOH in each refluxed solution= amount of standard HCl used to titrate each one of them. The difference in the amounts of KOH present (HCl used) in both flasks after reflux is the amount of KOH used in the saponification of the unknown ester.

Question 33

NEUTRALIZATION EQUIVALENT:
Step 1

Answer 33

Weigh accurately about 0.25 g of pire powdered palmitic acid

Question 34

NEUTRALIZATION EQUIVALENT:
Step 2

Answer 34

Dissolve iit in 12.5 mL ethanol in a 250-mL Erlenmeyer flask

Question 35

NEUTRALIZATION EQUIVALENT:
Step 3

Answer 35

Add 1 drop of phenolphthalein and titrate the solution w/ a standard 0.1N NaOH solution ( must be CO2 free) to a permanent faint-pink end-point

Question 36

NEUTRALIZATION EQUIVALENT:
Step 4

Answer 36

Calculate the neutralization equivalent