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प्रश्न
A student takes about 6 ml of distilled water in each of the four test tubes P, Q, R and S. He then dissolves an equal amount of four different salts namely, sodium chloride in 'P', potassium chloride in 'Q', calcium chloride in 'R' and magnesium chloride in 'S'. Next, he then adds 10 drops of soap solution to each test tube and shakes its contents. The test tubes in which scum (insoluble substance) is formed with soap are:
(A) P and Q
(B) Q and R
(C) R and S
(D) Q and S
उत्तर
Scum is formed by reaction of soap with calcium and magnesium salts in water. Test tubes R and S contain calcium chloride and magnesium chloride, respectively. Therefore, scum will be formed in these two tubes.
Hence, the correct option is C.
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संबंधित प्रश्न
A student adds 2 mL of acetic acid to a test tube containing 2 mL of distilled water. He then shakes the test tube well and leaves it to settle for some time. After about 5 minutes he observes that in the test tube there is :
(A) a clear transparent colourless solution
(B) a clear transparent pink solution
(C) a precipitate settling at the bottom of the test tube
(D) a layer of water the layer of acetic acid
While studying saponification reaction for the preparation of soap, a teacher suggested to a student to add a small quantity of common salt to the reaction mixture. The function of common salt in this reaction is to
(A) reduce the alkalinity of the soap
(B) reduce the acidity of the soap
(C) enhance the cleansing capacity of soap
(D) favour precipitation of soap
What are esters ?
What do you notice when acetic acid reacts with litmus?
Acetic acid is a typical acid. Write one equation in case of its reactions with a carbonate.
Fill in the blank with appropriate word/words.
Esterification is the reaction between carboxylic acid and ______ in presence of ____
State how the following conversions can be carried out:
Ethyl chloride to Ethyl alcohol
Ester is a sweet-smelling compound.
Give the balanced chemical equation of the following reaction:
Evolution of carbon dioxide by the action of ethanoic acid with NaHCO3.
Give the balanced chemical equation of the following reaction:
Neutralization of NaOH with ethanoic acid.
