Experiment #9: HYDROLYSIS OF SUCROSE (ACID VS BASE) Flashcards
Formula of Sucrose
C12H22O11
Characteristics of Sucrose
Soluble in water, slightly soluble in alcohol and ether, crystallizes in long slender needles
Sucrose is dextrorotatory which means
Rotating the plane of polarized light to the right
Upon hydrolysis it yields a mixture of
Glucose and Fructose
Glucose and Fructose are levorotatory which means
Plane of polarized light to the left
The mixture obtained in the hydrolysis of sucrose is known as
Invert sugar
Processs of hydrolysis of sucrose
Inversion
Inversion is carried on in the human intestine through the aid of the enzymes known as
Invertase and Sucrase
Sucrose is extracted chiefly from _____ and _____ and is commonly called_____
Sugarcane, Sugar beet, Cane Sugar
When heated to temperatures above 180C (356F) sucrose becomes the amorphous, brown, syrupy substance called
Caramel
Hydrolysis of sucrose is used to
Convert sucrose (non-reducing disaccharide) to glucose and fructose (reducing monosaccharide)
The only non-reducing disaccharide that does not reduce Cu+² solution (Benedict’s and Fehling’s test)
Sucrose
Sucrose is the only non-reducing disaccharide so it does not reduce Cu+² solution because
The glycosidic bond is formed between the two hemiacetal bonds, so there is no free aldehydic or ketonic group to give positive reducing properties.
This bond can be hydrolyzed and the individual components of _______ are the able to give ________ test
Sucrose(glucose +fructose), positive reducing
Fehling’s A composition
Blue colored aqueous solution of copper (II) sulfate (CuSO4)
Fehling’s B composition
Colorless aqueous solution of potassium sodium tartrate (Also known as Rochelle Salt)
Acidic (H2SO4) Observation
It turned to color red positive
Basic (NaOH) Observation
Blue, Negative
When sucrose goes through hydrolysis
The hydrolysis of sucrose generates an equimolar mixture of fructose and glucose, known as invert sugar
Why hydrolysis of sucrose called inversion
It’s because sucrose produce equimolecular mixture of glucose and fructose. Sucrose is dextrorotatory and glucose & fructose is levorotatory
Role of Sulfuric acid and Sodium Hydroxide
Catalyst
The rate of dehydration then accelerates as the acid heats up because the reaction is exothermic
2 chemicals compared as to which is the faster catalyst
Reagent used in Hydrolysis of Sucrose
Fehling’s reagent