मराठी

Paheli observed that most of the fish in the pond of her village were gradually dying. She also observed that the waste of a factory in their village is flowing into the pond which probably

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प्रश्न

Paheli observed that most of the fish in the pond of her village were gradually dying. She also observed that the waste of a factory in their village is flowing into the pond which probably caused the fish to die.

  1. Explain why the fish were dying.
  2. If the factory waste is acidic in nature, how can it be neutralised?
लघु उत्तर
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उत्तर

  1. Since the factory waste is being disposed off in the river, it can kill the fish because factory waste may contain acids or bases or other toxic materials.
  2. If the factory waste is acidic in nature, it can be neutralised by adding basic substances like lime before disposing off in the river.
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  या प्रश्नात किंवा उत्तरात काही त्रुटी आहे का?
पाठ 5: Acids, Bases and Salts - LONG ANSWER QUESTIONS [पृष्ठ ३२]

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एनसीईआरटी एक्झांप्लर Science [English] Class 7
पाठ 5 Acids, Bases and Salts
LONG ANSWER QUESTIONS | Q 25. | पृष्ठ ३२

संबंधित प्रश्‍न

One of the following is not an organic acid. This is:


What effect does the concentration of H+ (aq) ions have on the nature of a solution?


Write the chemical formula of ammonium chloride. Explain why an aqueous solution of ammonium chloride is acidic in nature? Illustrate your answer with the help of a chemical equation.

 

You are supplied with five solutions: A, B, C, D and E with pH values as follows: A = 1.8, B = 7, C = 8.5, D = 13, and E = 5

Classify these solutions as neutral, slightly or strongly acidic and slightly or strongly alkaline.

Which solution would be most likely to liberate hydrogen with magnesium powder. Give a word equation for each reaction.


Write the chemical name from the given formula.

H2SO4


What is the difference between : An alkali and a metal hydroxide?


Choosing the correct words given in brackets, complete the sentence given below:
A(n) ______ (acid/basic) salt is one in which the hydrogen of an acid has been partially replaced by a ______ (metal/non-metal).


Complete the following table and write one equation for each to justify the statement: 

Reactants

Products

Method

Soluble base + Acid (dil)

Salt + water

Neutralisation Titration

Metal + Non-metal

Salt (soluble/insoluble)

______

Insoluble base + ______

Salt (soluble) + water

______

Active metal + Acid (dil)

______ + ______

______

Soluble salt solution (A) + Soluble salt solution (B)

Precipitated salt + Soluble salt

______

Carbonate/bicarbonate + Acid (dil)

Salt + ______ + ______

Decomposition of carbonate

Chlorides/nitrates + Acid (conc.)

______ + ______

Decomposition of chlorides and nitrates


Turmeric is a natural indicator. On adding its paste to acid and base separately, which colours would be observed


Phenolphthalein is a synthetic indicator and its colours in acidic and basic solutions, respectively are ______.


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