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Question
State what are synthetic detergents. Explain experimentally how you will determine the advantage of synthetic detergents over soap using a sample of hard water.
Solution
Divide the sample of hard water into two parts.
To the first part of hard water add synthetic detergent and rub slowly with hand, it will lather easily.
Now add to the second part of hard water an ordinary piece of soap and rub with hand, it will not lather but scum is formed and soap is wasted.
Hence in case of hard water, it is advantageous to use synthetic detergent.
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RELATED QUESTIONS
What do you understand by
Temporary hard water
Name the substance which makes water temporarily hard
Explain with equation, what is noticed when permanent hard water is treated with
Slaked time
How will you distinguish between temporary hard water and permanent hard water?
Using given sample of temporary and permanent hard water, soft water, ordinary soap, detergent and washing soda how would you remove temporary hardness and permanent hardness from water using a chemical compound?
Name or state the following:
A substance added to remove both temporary and permanent hardness in water.
Soap lathers well in hard water.
Match the following.
| Universal solvent | Water pollutant |
| Hard water | Kills germs |
| Boiling | Ozonisation |
| Sterilization | Water |
| Sewage | Stomach ailments |
Give a reason for the following.
Hard water is not good for washing utensils.
What are the causes of temporary hardness and permanent hardness of water?
The pleasant taste of drinking water is due to the presence of a dissolved substance which includes air, CO2, and minerals.
What is soft water?
Which water is hard?
Which water is soft?
Take samples of water from different sources (like a tube well, a lake, a pond, or a river) and pour equal quantities of each sample of water into different test tubes. Measure the height of water in each test tube with a scale. Add one or two drops of liquid soap to each test tube. Shake each test tube five times and observe the height of the lather in each sample. Record your observations in the table. Which water is soft? Which water is hard? Can you say why?
