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प्रश्न
What is a chemical reaction?
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उत्तर
“Chemical reaction is a chemical change in which matter changes into a new substance or substances.”
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संबंधित प्रश्न
Name three biochemical catalysts found in the human body.
Complete and balance the following chemical equations
NaCI + `AgNO_3` `→`
Complete and balance the following chemical equation:
\[\ce{Pb(NO3)2 ->[Heat]}\]
Classify the following reaction as combination, decomposition, displacement, precipitation and neutralization. Also balance the equation.
\[\ce{NH3_{(g)} + HCl_{(g)} -> NH4Cl_{(s)}}\]
Write the missing reactants and products and balance the equations.
NaOH + ............... `→` NaCI + ...................
TRUE \ FALSE
Ammonia is a good oxidizing agent.
TRUE \ FALSE
Electrolytic refining is a method in which a thin coating of a metal is done over another metal.
What are chemical reactions?
State what you would observe when the following substance is heated in a glass test tube red lead.
Name: Two nitrates that do not produce nitrogen dioxide on heating.
What do you observe when HCI is passed through a silver nitrate solution.
What do you observe when CO2 is passed through lime water first and then a little in excess.
Represent the addition of dilute sulphuric acid to zinc by means of a chemical equation. State the function of the arrow between the reactants and products.
Match the chemical reactions in List I with the appropriate answer in List II.
| List I | List II | ||
| 1. | \[\ce{XY⇌[heat]X + Y}\] | A: | Displacement reaction |
| 2. | \[\ce{XY->X + Y}\] | B: | Double decomposition |
| 3. | \[\ce{X+Y- + A+B^-->X+B- + A+Y-}\] | C: | Endothermic reaction |
| 4. | \[\ce{X + YZ->XZ + Y}\] | D: | Thermal dissociation |
| 5. | \[\ce{X + Y->[heat]XY -\Delta}\] | E: | Decomposition reaction |
State the following reaction represent oxidation or reduction.
\[\ce{Ag->Ag+}\]
Assertion: The formation of iron oxide from iron is a chemical change.
Reason: For the rust to form from iron, it must be exposed to air and water.
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?
______ is a natural indicator.
Iron benches kept in lawns and gardens get____________. It is a _________ change because a new _________ is formed.
Iron and rust are the same substances.
