Difference between revisions of "ChemCollective-Virtual-Labs/C2/Acid-base-Titrations/English"
| Line 225: | Line 225: | ||
Vf (Final buret reading) = 29.991 mL | Vf (Final buret reading) = 29.991 mL | ||
| − | V2 = | + | V2 = Vi - Vf = 20.009 mL |
M2 (Molarity of NaOH) = 0.1 M | M2 (Molarity of NaOH) = 0.1 M | ||
| Line 415: | Line 415: | ||
M2 (Molarity of HCl) = 1 M | M2 (Molarity of HCl) = 1 M | ||
| − | V1 (Volume of | + | V1 (Volume of NH3) = 20 mL |
M1V1= M2V2 | M1V1= M2V2 | ||
Latest revision as of 17:53, 24 March 2017
| Time | Narration |
| Slide Number 1
Title Slide |
Welcome to this spoken tutorial on Acid-Base Titrations using Vlabs. |
| Slide Number 2
Learning Objectives |
In this tutorial we will learn to standardise:
Strong-Acid with Strong-Base and Strong-Acid with Weak-Base using titration method. |
| Slide Number 3
Pre-requisites www.spoken-tutorial.org. |
To follow this tutorial you should be familiar with-
ChemCollective Vlabs interface. If not for relevant tutorials, please visit our website. |
| Slide Number 4
System Requirement |
Here I am using
Mac OS version 10.10.5 ChemCollective Vlabs version 2.1.0 Java version 8.0. |
| Point to the window. | Here I have opened Virtual Chemistry labs application window.
Default lab setup window opens. |
| Cursor on Workbench. | Let us begin the demonstration with standardization of-
strong-acid with strong-base. |
| Double-click on Strong-acids cabinet.
Double-click on 0.1M Hydrochloric acid(HCl). Click on Cabinet icon to close. |
We will retrieve required chemicals from stockroom.
Double-click on Strong-acids cabinet. Now double click to Select, 0.1 M Hydrochloric acid from the list. Close the cabinet. |
| Double-click on Strong-bases cabinet.
Double-click on 0.1 M Sodium hydroxide(NaOH). |
From the Strong-bases cabinet, select, 0.1 M sodium hydroxide.
Close the cabinet. |
| Double-click on Indicators cabinet.
Click on Phenolphthalein, drag and drop on the workbench. |
From the Indicators cabinet select Phenolphthalein.
Drag the bottle and drop on the workbench. Close the cabinet. |
| Click on Glassware menu.
Double-click on 250 mL Erlenmeyer Flask. 10 mL Pipet, 50 mL Buret. |
Click on Glassware menu.
Now select, 250 mL Erlenmeyer Flask. 10 mL Pipet and 50 mL Buret.
|
| Right-click on the flask, from the sub-menu select Rename. | Rename the Erlenmeyer Flask as A1. |
| Place the 10 mL Pipet on flask containing Hydrochloric acid(HCl).
In the Transfer Amount input-bar type 10. Click on Withdraw. Drag the Pipet on to flask A1. In the Transfer Amount input-bar type 10. Click on Pour. Repeat the process again. |
Using pipet transfer 20 mL of Hydrochloric acid(HCl) into flask A1.
Place the 10 mL pipet on flask containing Hydrochloric acid(HCl). In the Transfer Amount input-bar type 10. Click on Withdraw. Drag the Pipet on to flask A1. In the Transfer Amount input-bar type 10. Click on Pour. We require 20 mL of HCl for this titration. Since we have 10 mL pipet we need to use it twice to transfer 20 mL of Hydrochloric acid(HCl). |
| Drag and Place Phenolphthalein bottle over Flask A1. | Place Phenolphthalein bottle over Flask A1. |
| Type 0.3 in the Transfer Amount input bar.
Click on pour. Drag and keep Phenolphthalein bottle aside. |
Type 0.3 in the Transfer Amount input bar.
Click on pour. Keep Phenolphthalein bottle and Hydrochloric acid(HCl) aside. |
| Drag and place 0.1M Sodium hydroxide(NaOH) over the buret.
Type 50 in the Transfer Amount input bar. Click on pour. Keep NaOH flask aside. |
Drag and place 0.1 M Sodium hydroxide(NaOH) over the burete.
Transfer 50 mL of Sodium hydroxide(NaOH) into the buret. Observe that, burete reading is not zero. This is because the lower part of the burete is also filled. Keep Sodium hydroxide(NaOH) flask aside. |
| Drag and place the burete over Flask A1
Point to the Solution Info panel. |
Place the burete over Flask A1.
Click on the buret. Note the initial volume of Sodium hydroxide(NaOH) in the buret from the Solution Info panel. |
| Click on Tools menu, select Realistic Transfer.
Click on Pour button gradually. |
Change the Transfer Bar to Realistic Transfer.
Click on Pour button gradually. Reaction between Hydrochloric acid(HCl)and Sodium hydroxide(NaOH) is equimolar. So, end point is expected around 20 mL. |
| After adding 19 mL of Sodium hydroxide(NaOH), change the transfer mode to Significant Figures Transfer.
Click on Tools menu, select Transfer Bar. Click on Significant Figures Transfer. |
To obtain accurate volume for end-point detection;
After adding 19 mL of Sodium hydroxide(NaOH), change the Transfer Bar to Significant Figures Transfer. |
| In the Transfer Amount input bar type 0.01.
Click on pour. |
In the Transfer Amount input bar type 0.01.
This will transfer 0.01 mL of Sodium hydroxide(NaOH) for every click on pour button. Click on pour. |
| Cursor on Solution Info panel. | Observe pH change in the Solution Info panel. |
| Click on pour button.
Point to flask A1. |
Click on pour button, observe the faint pink colour in Flask A1.
This is the end-point of titration. |
| Click on the buret.
Point to solution info panel. |
Click on the buret.
Note the volume of remaining Sodium hydroxide(NaOH)from the solution info panel. |
| Slide Number 5
Calculations. Vi (Initial buret reading of NaOH) = 50 mL Vf (Final buret reading) = 29.991 mL V2 = Vi - Vf = 20.009 mL M2 (Molarity of NaOH) = 0.1 M V1 (Volume of HCl) = 20 mL M1V1= M2V2 M1x 20 = 0.1 x 20.02 M1 = 0.1 M |
Final calculations are shown on this slide.
We have used the formula M1V1= M2V2 to calculate M1 that is molarity of Hydrochloric acid(HCl). We have obtained the value of M1 as 0.1 M. |
| Click on Remove tool. | To clear the workbench, select each component .
To remove the selected component, click on remove tool. Similarly remove all the components from the workbench. |
| Cursor on workbench.
Double-click on Strong-acid cabinet. Double-click on 1M HCl. Double-click on Weak-base cabinet. Double-click on 1M Ammonia. Double-click on Indicator cabinet. Double-click on methyl orange. Close the cabinet. |
Let us retrieve solutions for the titration of Strong-acid with Weak-base.
Double-click on Strong-acids cabinet and select 1 M HCl . Now double click on Weak-bases cabinet and select 1 M Ammonia. For this experiment let us choose methyl orange as indicator. Drag and place it on the workbench. |
| Double-click on Glassware menu.
Double-click on 250 mL Erlenmeyer Flask, 10 mL Pipet, 50 mL Buret. |
Double-click on Glassware menu.
Select the following glassware; 250 mL Erlenmeyer Flask. 10 mL Pipet and 50 mL Buret. Rearrange the apparatus. |
| Right-click on the flask, from the sub-menu select Rename.
In the dialog-box type A2. |
Rename the Erlenmeyer Flask as A2. |
| Place the 10 mL pipet on flask containing Ammonia. | Change the Transfer Bar to precise transfer.
Using pipet transfer 20 mL of Ammonia into flask A2. Place 10 mL pipet on flask containing Ammonia. |
| In the Transfer Amount input-bar type 10.
Click on Withdraw. Drag the Pipet on to flask A2. |
In the Transfer Amount input-bar type 10.
Click on Withdraw. Drag the Pipet on to flask A2. |
| In the Transfer Amount input-bar type 10.
Click on Pour Repeat the process again. |
In the Transfer Amount input-bar type 10.
Click on Pour. We need 20 mL of Ammonia, so pipette out twice into flask A2. |
| Drag and Place methyl orange bottle over Flask A2.
Type 0.3 in the Transfer Amount input bar. Click on pour. Drag and keep methyl orange bottle aside. |
Transfer 0.3 mL of methyl orange into flask A2.
Keep methyl orange bottle aside. |
| Drag and place 1 M HCl over the buret
Type 50 in the Transfer Amount input bar. Click on pour. Keep HCl flask aside. |
Drag and place 1 M HCl over the buret.
Transfer 50 mL of HCl into the buret. |
| Drag and place the buret over Flask A2. | Place the buret over flask A2. |
| Cursor on workbench. | Let us start the titration. |
| Click on Tools menu, select Realistic Transfer.
Click on Pour button gradually. |
Change the Transfer Bar to Realistic Transfer.
Click on Pour button gradually. Reaction between Hydrochloric acid(HCl) and ammonia is equimolar. So, end point is expected around 20 mL. |
| After adding 19 mL of HCl,
Click on Tools menu, select Transfer Bar. Click on Significant Figures Transfer. |
To obtain accurate volume for end-point detection;
After adding 19 mL of HCL, change the Transfer Bar to Significant Figures Transfer. |
| In the Transfer Amount input bar type 0.01.
Click on Pour. In the Transfer Amount input bar type 0.01 click on pour. |
This will transfer 0.01 mL of Hydrochloric acid(HCl) for every click on pour button.
As we titrate observe the increase in temperature. |
| Cursor on Solution Info panel. | Observe the pH changes. |
| In the Transfer Amount input bar type 0.01.
Click on Pour. Cursor on Solution Info panel. |
Transfer a few more drops of Hydrochloric acid(HCl).
Observe the change in colour in Flask A2 to orange colour. Note the final volume of Hydrochloric acid(HCl) from the Solution info panel. Your final volume may be different from the value shown here. |
| Click on Spectrometer radio button.
Point to the Absorbance in the Solution info panel. |
Click on Spectrometer radio button.
Note the Absorbance in the Solution info panel. |
| Slide Number 6
Calculations Vi (Initial buret reading of HCl) = 50 mL Vf (Final buret reading) = 29.991. V2 = Vi - Vf = 20.009 M2 (Molarity of HCl) = 1 M V1 (Volume of NH3) = 20 mL M1V1= M2V2 M1 x 20 = 1 x 20.009 M1 = 1 M |
Here are the final calculations.
Molarity of ammonia is 1M. |
| Slide Number 7
Summary |
Let us summarize
In this tutorial we have learnt to standardise; Strong-Acid with Strong-Base and Strong-Acid with Weak-Base using titration method. |
| Slide Number 8
Assignment |
As an assignment,
Standardize a solution of ethanoic acid (acetic acid) using titration method. Hint- All the necessary solutions and apparatus are available in default lab setup window. |
| Slide Number 9
About Spoken Tutorial project |
The video at the following link summarizes the Spoken Tutorial project.
Please download and watch it. |
| Slide Number 10
Spoken Tutorial workshops |
The Spoken Tutorial Project team-
conducts workshops using spoken tutorials and gives certificates on passing online tests. For more details, please write to us. |
| Slide Number 11
Forum for specific questions- Do you have questions in THIS Spoken Tutorial? Please visit this site Choose the minute and second where you have the question Explain your question briefly Someone from our team will answer them. |
Please post your timed queries on this forum. |
| Slide Number 12
Acknowledgement |
Spoken Tutorial Project is funded by NMEICT, MHRD, Government of India.
More information on this mission is available at this link. |
| This tutorial is contributed by Snehalatha Kaliappan and Madhuri Ganapathi from IIT-Bombay.
Thank you for joining. |
