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प्रश्न
A bag of cement lying in the open gets wet due to rain during the night. The next day the sun shines brightly. Do you think the changes, which have occurred in the cement, could be reversed?
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उत्तर
In this case, the changes cannot be reversed. This is because the cement that hardens up after getting wet cannot be obtained back.
संबंधित प्रश्न
Name the type of chemical reaction shown by the following equation:
NaOH + HCl → NaCl + H2O
Define a photochemical reaction.
Give a chemical test to distinguish between the following gases.
H2 and CO2
Give a chemical test to distinguish between the following gases.
HCl and H2S
What do you observe when CO2 is passed through lime water first and then a little in excess.
What is a chemical reaction?
Complete the statement by filling in the blank with the correct word:
The reddish-brown precipitate obtained during a double decomposition precipitation reaction between an iron salt and alkali is __________.
When lithium metal is placed in hydrochloric acid, _______ gas is evolved.
Iron and rust are the same substances.
______ is the chemical name of limestone.
