Determination of Order and Rate Constant using Sono Chemical Reactor


To determine the specific reaction rate constant for saponification of ethyl acetate with NaOH in the given Sono chemical reactor.


Experimental set up, round bottomed flask, beakers, burette etc.


Ultrasound is the name given to sound waves having frequencies higher than those to which human ears can’t respond, i.e., greater than 16 kHz. Ultrasound waves can be transmitted through any material possessing elastic character. Ultrasound can be applied in the fields of biology, dentistry, plastics and polymers. Ultrasound has been employed for specific chemical applications. Cavitation is an effect which is responsible for the chemical effects.

In the ultrasonic cleaning, bath water is present for transferring the ultrasound from the generators to the reaction vessel. The reaction vessel is submerged in the water at a level where the liquid in the flask is just above the surface of the water. After sonication is started, the flask is adjusted to the point where cavitation (bubbles) is maximum. The temperature of the water is kept constant by cooling,


1. Take about 200 ml of 0.lN NaOH and 150 ml of 0.05N ethyl acetate in the round bottomed flask and place it in the ultrasonic bath.

2. Switch on the bath and allow the reaction to take place for 45 min.

3. After 5, 10, 15, 20,25, 30 minutes take about 10 m1 of the reaction mixture in a conical flask containing 10 ml of 0.1 N HCl to arrest the reaction.

4. Titrate the mixture against 0.1 N NaOH using phenolthalein indicator.

5. 5.After 45 min. take 10 ml of reaction mixture in a empty conical flask and titrate against 0.1N NaOH

6. Repeat the same experiment outside the bath i.e., in a batch reactor.


Standardization of NaOH:

Sl. No. Volume of NaOH taken (ml) Volume of NaOH rundown, ml
Initial Final

Volume of oxalic acid taken in the conical flask = V1
Normality of oxalic acid = N1
Volume of NaOH run down from the burette (x)= V2

Normality of NaOH

Standardization of HCI:

Sl. No. Volume of NaOH taken (ml) Volume of NaOH rundown, ml
Initial Final

Volume of HCI taken m the conical flask = V3
Volume of NaOH run down from the burette = V4
Normality of HCl

Amount of NaOH rundown for 25 ml of HCl = Z ml


Sl. No Time (min) Vol. NaOH (from burette)
(y) ml Concentration of NaOH
CA = (Z-y) * N2
1. 5
2. 10
3. 15
4. 20
5. 25
6. 30
7. 35

From graph,
Sl. No.


¬¬¬¬¬Plot a graph of CA Vs time and draw tangents at different points,

Plot versus and determine the slope 'n'

[ = ln k + n ]

k = min-l


Order of the reaction ‘n’ =
Specific rate constant ‘k’ =¬ min-1

Viva Voce:

1. What do you understand by the term Sono Chemical Reactor?
2. What is the frequency level maintained in the Sono Chemical Reactor?
3. What are the practical applications of Sono Chemical Reactor?
4. What are the advantages of Sono Chemical Reactor?
5. What does the graph of the Sono Chemical Reactor denote?