During an experiment, Mayank made the given observations. Which of these does not indicate that a chemical reaction has occurred?

Evolution of gas

Change of colour

Formation of precipitate

Mass change

Change of state

Change in energy

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Solution

Chemical Reactions are characterized by changes that are quite easily observed and those changes are:

Evaluation of gas

Change of colour

Formation of precipitate

Change of state

Change in energy

During a chemical reaction, there is no change in the total mass of the substance as the mass or energy cannot be created nor destroyed; it can only be transferred within the closed system.

So change in mass does not indicate that a chemical reaction has occurred.

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Similar questions

Which of the following observations helps to determine whether a chemical reaction has taken place or not?

(i) Change in state.

(ii) Change in colour.

(iii) Change in shape

(iv) Evolution of gas.

(v) Change in temperature.

The chemical reaction between quicklime and water is characterised by :
(a) evolution of hydrogen gas

(b) formation of slaked lime precipitate

(d) change in colour of the product

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