Advertisements
Advertisements
प्रश्न
State the various characteristics of chemical reactions.
Advertisements
उत्तर
Following are the various characteristics of a chemical reaction:
- Evolution of gas: Zinc and dilute sulphuric acid react to form zinc sulphate with the evolution of hydrogen gas.
- Formation of precipitate: Sulphuric acid and barium chloride react to form white precipitates of barium sulphate.
- Change in colour: Purple colour of potassium permanganate solution on addition of citric acid changes to colourless solution.
- Change in temperature: Barium hydroxide and ammonium chloride react to form barium chloride, ammonia and water. This is an endothermic reaction in which heat is absorbed, causing the temperature to fall.
- Change in state: Combustion of candle wax (solid) leads to the formation of water (liquid) and carbon dioxide (gas).
APPEARS IN
संबंधित प्रश्न
Translate the following statement into chemical equation and then balance the equation:
Carbon disulphide burns in air to give carbon dioxide and sulphur dioxide.
What is a chemical equation? Explain with the help of an example.
Is Burning of natural gas an endothermic reaction or an exothermic reaction?
Write symbolic representation for the following word equation and balance them :
Carbon + Oxygen → Carbon dioxide.
Balance the following equation. Also name the product formed.
CO2 + C → CO
Balance the following equation. Also name the product formed.
PbCO3 → PbO +CO2
In electrolysis of water, why is the volume of gas collected over one electrode double that of gas collected over the other electrode?
Name the substances that are getting oxidised and reduced in the process.
A student mixes sodium sulphate powder in barium chloride powder. What change would the student observe on mixing the two powders? Justify your answer and explain how he can obtain the desired change.
A chemical reaction is generally accompanied by certain external indications or characteristics. These include – change of – (a) colour (b) state (c) smell (d) evolution of gas (e) formation of precipitate (f) evolution or absorption of heat. With reference to change of colour – state the change in colour seen when the following are heated – mercury [II] oxide.
Representation of the results of a chemical change – is a chemical equation.
For the equation: FeCl3 + 3NH4OH 3NH4Cl + Fe(OH)3 ↓
Answer the following:
Write the word equation for the above molecular equation.
Give word equation for the following chemical reaction and give the names of the product formed.
ZnCO3 → ZnO + CO2
Balance the following simple equation:
H2 + O2 → H2O
Balance the following simple equation:
\[\ce{N2 + H2 <=> NH3}\]
Balance the following simple equation:
Mg + CO2 → MgO + C
CaCO3 + 2HCl[dil.] → CaCl2 + H2O + CO2 [g]
State the information not conveyed by the above chemical equation.
Underline the compound in the equation given below, it is incorrectly balanced and write the correct balancing for the same.
Fe2O3 + 2H2 → 2Fe + 3H2O
Match the columns.
| Reactants | Products | Types of chemical reaction | ||
| 1. | MgH2 | → | Mg + H2 | Endothermic |
| 2. | 2H2S + SO2 | → | 3S + 2H2O | Oxidation |
| 3. | CaO + H2O | → | Ca(OH)2 + heat | Exothermic |
| Redox | ||||
Balance the given chemical reaction as per the instructions below.
\[\ce{NaOH + H2SO4 -> Na2SO4 + H2O}\]
Write names of reactants and products of chemical reaction.
Which of the following is not a physical change?
