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प्रश्न
Would you be able to check if water is hard by using a detergent?
Would you be able to check whether water is hard by using a detergent? Why?
उत्तर १
Detergent gives lather with hard and soft water both, while a soap gives lather with soft water only. Thus, it is not possible to check if water is hard; by using a detergent.
उत्तर २
Detergents are ammonium or sulphonate salts of long chain carboxylic acids. Unlike soap,they do not react with calcium and magnesium ions present in hard water to form scum.They give a good amount of lather irrespective of whether the water is hard or soft. This means that detergents can be used in both soft and hard water. Therefore, it cannot be used to check whether the water is hard or not.
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संबंधित प्रश्न
In the neighbourhood of your school, hard water required for an experiment is not available. Select from the following group of salts available in your school, a group each member of which, if dissolved in distilled water, will make it hard:
(a) Sodium chloride, calcium chloride
(b) Potassium chloride, sodium chloride
(c) Sodium chloride, magnesium chloride
(d) Calcium chloride, magnesium chloride
A student takes four test tubes marked P, Q, R and S of 25 mL capacity and fills 10 mL of distilled water in each. He dissolves one spoon full of four different salts in each as − KCl in P, NaCl in Q, CaCl2 in R and MgCl2 in S. He then adds about 2 mL of a sample of soap solution to each of the above test tubes. On shaking the contents of each of the test tubes, he is likely to observe a good amount of lather (foam) in the test tubes marked
(a) P and Q
(b) R and S
(c) P, Q and R
(d) P, Q and S
Why does micelle formation take place when soap is added to water? Will a micelle be formed in other solvents such as ethanol also?
Explain the formation of scum when hard water is treated with soap.
What change will you observe if you test soap with litmus paper (red and blue)?
Distinguish between esterfication and saponification reaction with the help of the chemical equations for each.
While studying the saponification reaction, what do you observe when you mix an equal amount of colourless vegetable oil and 20% aqueous solution of NaOH in a beaker?
(A) The colour of the mixture has become dark brown
(B) A brisk effervescence is taking place in the beaker
(C) The outer surface of the beaker has become hot
(D) The outer surface of the beaker has become cold
Mention the essential material (chemicals) to prepare soap in the laboratory. Describe in brief the test of determining the nature (acidic/alkaline) of the reaction mixture of saponification reaction.
Explain esterification reaction with the help of a chemical equation. Describe an activity to show esterification.
State one advantage of soaps over detergent.
Why is soap not suitable for washing clothes when the water is hard?
The soap molecule has a ______.
In a soap micelle, the soap molecules are arranged radially with:
(a) ionic ends directed towards the centre and hydrocarbon ends directed outwards
(b) hydrocarbon ends directed towards the centre and ionic ends directed outwards
(c) both ionic ends and hydrocarbon ends directed toward the centre
(d) both hydrocarbon ends and ionic ends directed outwards
Give the reason of formation of scum when soaps are used with hard water.
Differentiate between:
Detergents and Soaps.
What is the difference between soaps and detergents? State, in brief, the cleansing action of soaps in removing an oily spot from a fabric. Why are soaps not very effective when a fabric is washed in hard water? How is this problem resolved?
What are the differences between Bath soap and soap for washing clothes?
The soap molecule has a
- Write the formula and draw electron dot structure of carbon tetrachloride.
- What is saponification? Write the reaction involved in this process.
What are the similarities between Soap and synthetic detergent.
