PoojaMoolya: Created page with "{| border=1 ||'''Time''' ||'''Narration''' |- ||00:01 || Welcome to this tutorial on '''Dilutions and pH measurement.''' |- || 00:06 || In this tutorial, we will learn..."

2019-01-30T10:39:22Z

Created page with "{| border=1 ||'''Time''' ||'''Narration''' |- ||00:01 || Welcome to this tutorial on '''Dilutions and pH measurement.''' |- || 00:06 || In this tutorial, we will learn..."

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{| border=1
||'''Time'''
||'''Narration'''

|-
||00:01
|| Welcome to this tutorial on '''Dilutions and pH measurement.'''

|-
|| 00:06
|| In this tutorial, we will learn to measure: Change in pH for solutions of acid and base on dilution.

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||00:14
|| Variation in pH by '''common-ion''' effect for weak acids and bases.

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||00:20
|| To follow this tutorial, you should be familiar with, '''ChemCollective Vlabs''' interface.

|-
||00:27
|| If not, for relevant tutorials, please visit our website.

|-
|| 00:32
|| Here, I am using: '''Mac OS''' version 10.10.5

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||00:37
|| '''ChemCollective Vlabs''' version 2.1.0

|-
||00:42
|| '''Java''' version 8.

|-
|| 00:45
|| For this demonstration, let us dilute - 0.1 molar Hydrochloric acid to 0.01 molar Hydrochloric acid.

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||00:54
|| 0.1 molar sodium hydroxide to 0.01 molar sodium hydroxide.

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||01:00
|| For this experiment, 2 ml of 0.1 M Hydrochloric acid or sodium hydroxide is diluted to 20 ml with distilled water.

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|| 01:12
|| I have opened a''' “Virtual Chemistry labs” application''' '''window'''.

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|| 01:18
|| '''Stockroom explorer''' opens with solutions of various acids and bases.

Double-click on '''Strong-acids cabinet'''.

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||01:29
|| A list of acidic solutions with various strengths opens.

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|| 01:34
|| Double-click to choose 0.1 Molar Hydrocloric acid.

Click on the flask, observe the pH on the '''pH Meter'''.

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||01:44
|| Note that pH Meter reads 1.

Click on the radio button near '''Strong-acids cabinet''', to close the list.

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|| 01:54
|| Next, from '''Stockroom explorer''', double-click on '''Strong-bases cabinet'''.

A list of basic solutions with various strengths opens.

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||02:05
|| Double-click to choose point one molar Sodium Hydroxide.

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|| 02:10
|| Click on the flask, observe the pH on the '''pH Meter'''.

Note that pH Meter reads 13.

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||02:19
|| Click on the radio button near '''Strong-bases''' cabinet to close the list.

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||02:25
|| Double click on '''Distilled water''' icon from '''Stockroom explorer'''.

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|| 02:30
|| Let us now add the required apparatus to the workbench.

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|| 02:35
|| Click on '''glassware '''icon.

Select '''Graduated Cylinders.'''

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||02:41
|| From the sub-menu, select 10 mL''' Graduated Cylinder '''to add''' '''to the workbench.

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|| 02:48
|| For this experiment, we need two '''Graduated cylinders.'''

Right-click on the Graduated Cylinder.

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||02:55
|| From the context menu, select '''copy'''.

Place the cursor at a different place.

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||03:02
|| Right-click and choose '''Paste''' option from the '''menu'''.

|-
|| 03:06
|| Click on '''glassware '''icon.

Select '''Erlenmeyers.'''

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||03:12
|| From the sub-menu, select 250 mL '''Erlenmeyer Flask.'''

We require two flasks. Right-click to '''copy''' and '''paste'''.

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|| 03:24
|| Label the '''Graduated Cylinders''' as '''A''' and '''B.'''

Right-click on the '''Graduated Cylinder.'''

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||03:32
|| From the '''Context-menu,''' select '''Rename''' option.

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||03:37
|| A text box opens. Type''' A''' in the text box and click on '''Ok '''button.

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||03:45
|| Similarly, label the other '''Graduated Cylinder '''as '''B.'''

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||03:51
|| Similarly, label '''Erlenmeyer Flasks '''as '''A''' and '''B.'''

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|| 03:59
|| Place each set of apparatus at a different position on the workbench.

Use set''' A '''for acids and set''' B''' for bases.

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|| 04:11
|| To perform this experiment, we will dilute 2 ml of 0.1 Molar Hydrocloric acid with 18 ml of distilled water.

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||04:22
|| Drag 0.1 molar '''Hydrochloric acid '''flask over to the '''Graduated Cylinder A.'''

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||04:30
|| In the '''Transfer amount ''' input bar, type '''2'''.

Click on '''Pour'''.

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||04:37
|| Move the flask aside.

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|| 04:40
|| Move the '''Distilled '''water tank over '''Flask A'''.

In the '''Transfer amount''' input bar, type '''18'''.

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||04:48
|| Click on '''Pour'''. Move the''' Distilled water '''aside.

|-
|| 04:53
|| Place the '''Graduated Cylinder A '''over''' Flask A'''.

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||04:59
|| Change the transfer mode to '''Realistic transfer'''.

Click on''' Pour''' button gradually.

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||05:07
|| Move the '''Graduated Cylinder A '''aside.

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||05:11
|| Click on '''Flask A,''' observe the pH on the '''pH meter.'''

'''pH meter''' reads 2.

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|| 05:19
|| Similarly, let us dilute 0.1 Molar Sodium hydroxide and measure pH.

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|| 05:26
|| Measure 2 mL of 0.1 Molar Sodium hydroxide in '''Graduated Cylinder B.'''

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||05:34
|| Drag 0.1 molar '''Sodium Hydroxide '''flask over to '''Graduated Cylinder B.'''

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||05:41
|| Using '''Tools''' menu, change the transfer mode to '''Precise transfer'''.

|-
|| 05:47
||In the '''transfer amount '''input bar, type '''2'''.

Click on '''Pour'''.

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|| 05:53
|| Move the flask aside.

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|| 05:56
|| Move the '''Distilled '''water tank over '''Flask B'''.

|-
|| 06:00
|| In the '''Transfer amount '''input bar, type '''18'''.

Click on '''Pour'''.

|-
|| 06:06
||Move the '''Distilled''' water aside.

|-
||06:09
|| Transfer 2 ml of '''sodium hydroxide''' from '''Graduated Cylinder B '''to''' Flask B.'''

Place the '''Graduated Cylinder B '''over''' Flask B'''.

|-
|| 06:22
|| Change the transfer mode to '''realistic transfer'''.

Click on '''Pour''' button gradually.

|-
|| 06:29
|| Move the '''Graduated Cylinder B '''aside.

|-
|| 06:33
|| Click on '''Flask B,''' observe the pH on the pH meter.

pH meter reads 12.

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||06:41
|| Here is a table which shows results of our experiment.

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|| 06:46
||pH of 0.1 Molar Hydrocholric acid is 1. When diluted, acidity decreases.

After dilution, pH was found to be 2.

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|| 06:59
||Similarly, pH of 0.1 Molar Sodium Hydroxide is 13. When diluted, alkalinity decreases.

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|| 07:09
||Hence, after dilution, pH was found to be 12.

Since pH is a logarithmic scale, for every 10 times dilution pH changes by 1 unit.

|-
| 07:23
| Back to the workbench.

For the next experiment, load a new workbench using '''File''' menu.

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|| 07:31
||Click on Workbench 2.

|-
| 07:34
|Let us study the variation in pH by '''common ion''' effect.

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| 07:40
| We will demonstrate this, using weak acids and weak bases.

|-
|07:46
| For this demonstration , we will use two examples-

1. Ethanoic acid and its conjugate base, sodium ethanoate.

2. Ammonia and its conjugate acid, Ammonium Chloride.

|-
| 08:00
| Back to workbench.

Place the required chemicals from the S'''tockroom explorer''' on the workbench.

|-
| 08:08
| From '''Stockroom explorer''', double-click on '''Weak-acids''' cabinet.

|-
| 08:14
| A list of weak acid solutions with various strengths opens.

Double-click to choose''' 1 molar Ethanoic acid'''.

Close the list.

|-
| 08:25
| Again from '''Stockroom explorer''', double-click on '''Weak-bases''' cabinet.

A list of weak bases with various strengths opens.

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| 08:36
| Double-click to choose '''1 molar Ammonia solution.'''

Close the list.

|-
|08:43
| Double-click on '''Conjugate-acids''' cabinet.

|-
| 08:47
| Double-click on 1 molar '''Ammonium Chloride''' solution.

Close the list.

|-
| 08:54
| Double-click on '''Conjugate-bases''' cabinet.

Double-click on 1 molar '''Sodium Ethanoate solution''' from the list.

Close the list.

|-
| 09:05
| Next, click on '''new glassware''' icon. Select 250 ml '''Beaker'''.

|-
| 09:12
| We need 4 '''Beakers '''for this experiment.

Right-click on the '''Beaker'''.

Using '''copy''' and '''paste''' option make 3 copies of the '''Beaker'''.

|-
|09:24
| Label the '''beakers''' as '''A, B, C''' and '''D'''.

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| 09:30
| Place the Beakers A and B to one side of the workbench.

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| 09:35
| Place the Beakers C and D on other side of the workbench.

|-
| 09:40
| Place Ethanoic acid and its conjugate base, Sodium Ethanoate on one side.

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| 09:47
| Place Ammonia and its conjugate acid Ammonium Chloride on the other side.

|-
| 09:54
| Transfer 25 ml of '''Ethanoic acid '''in beakers '''A''' and '''B '''using '''Precise''' transfer mode.

Type '''25''' in the '''transfer amount''' input bar.

|-
| 10:08
| Click on '''pour'''.

Similarly, transfer 25 ml of '''Ethanoic acid '''to''' '''beaker '''B'''.

|-
| 10:16
| Move the flask aside.

|-
| 10:19
| Transfer 25 ml of '''Ammonia solution''' into beakers '''C '''and '''D'''.

|-
| 10:30
| Move the flask aside.

|-
|10:32
| To demonstrate the effect of common ion- Transfer 25 ml of Sodium ethanoate into beaker B.

|-
| 10:41
| Place 1 molar '''Sodium ethanoate''' flask over beaker '''B'''.

|-
| 10:47
| Type '''25''' in the '''transfer amount''' input bar.

Click on '''pour'''.

Keep the flask aside.

|-
| 10:55
| To check the pH of 1M Ethanoic acid present in beaker A, click on beaker A.

pH meter shows pH value of 2.38.

|-
| 11:10
| Click on beaker B. pH meter shows value of 4.76 .

|-
| 11:17
| Now transfer 25 ml of Ammonium Chloride into beaker D.

Place 1 Molar '''Ammonium Chloride '''flask over beaker '''D.'''

|-
| 11:29
| Type '''25''' in the '''transfer amount''' input bar.

Click on '''pour'''.

Keep the flask aside.

|-
| 11:38
| To check the pH of 1molar Ammonia present in beaker C, click on beaker C.

|-
| 11:46
| pH meter shows pH value of 11.62.

|-
|11:52
| Click on beaker D. pH meter shows pH value of 9.25.

Now, let us tabulate the results.

|-
| 12:03
| Due to the presence of common ion that is ethanoate ion, ionization of ethanoic acid decreases.

Hence pH value increases.

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| 12:16
| Similarly, due to the presence of ammonium ion, ionization of Ammonia decreases.

Hence pH value decreases.

|-
| 12:26
| Let us summarize.

In this tutorial, we have learnt to measure- Change in pH for solutions of 0.1 Molar Hydrochloric acid and 0.1 Molar Sodium Hydroxide on dilution.

|-
| 12:43
| Variation in pH by '''common-ion''' effect for ethanoic acid and ammonia solutions.

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|12:51
| As an assignment: Measure change in pH for- 1 Molar and 0.01 Molar Sulphuric acid.

|-
| 12:59
| 1 Molar and 0.01 Molar Sodium hydroxide.

|-
|13:04
| The video at the following link summarizes the '''Spoken Tutorial '''project.

Please download and watch it.

|-
| 13:11
| The '''Spoken Tutorial Project '''team: conducts workshops using spoken tutorials and

gives certificates on passing online tests.

For more details, please write to us.

|-
|13:24
| Please post your timed queries in this forum.

|-
|13:29
| Spoken Tutorial Project is funded by NMEICT, MHRD, Government of India.

More information on this mission is available at this link.

|-
| 13:40
| This tutorial is contributed by Snehalatha Kaliappan and Madhuri Ganapathi from '''IIT-Bombay'''.

Thank you for joining.
|-
|}

ChemCollective-Virtual-Labs/C2/Dilutions-and-pH-Measurement/English-timed - Revision history

PoojaMoolya: Created page with "{| border=1 ||'''Time''' ||'''Narration''' |- ||00:01 || Welcome to this tutorial on '''Dilutions and pH measurement.''' |- || 00:06 || In this tutorial, we will learn..."