Advertisements
Advertisements
प्रश्न
Write any two observations in an activity which may suggest that a chemical reaction has taken place. Give an example in support of your answer.
Advertisements
उत्तर
Two observations that may suggest that a chemical reaction has taken place are
(i) evolution of a gas and
(ii) change in temperature.
For example, zinc granules react with dilute sulphuric acid to evolve hydrogen gas, which is easily observed by the bubbles of hydrogen gas appearing around zinc granules. Also, the flask becomes hot, which shows heat is evolved during the reaction—that is, change in temperature.
Zn + H2SO4 → ZnSO4 + H2↑ + Heat
संबंधित प्रश्न
Balance the following chemical equation.
\[\ce{NaCl + AgNO3 -> AgCl + NaNO3}\]
Translate the following statement into chemical equation and then balance the equation:
Phosphorus burns in oxygen to give phosphorus pentoxide.
Complete and balance the following equation:
CA (OH)2 + ............. 
CaCO3 + H2O
What is meant by chemical reaction? Explain with the help of an example.
Zinc oxide reacts with carbon, on heating, to form zinc metal and carbon monoxide. Write a balanced chemical equation for this reaction. Name (i) oxidising agent, (ii) reducing agent, in this reaction.
Explain the following reaction with one suitable example .
Decomposition reaction
Balance the following chemical equation :
Na2CO3 + HCl → NaCI + H2O + CO2
What information do you get from the equation H2+ Cl2 → 2HCl ?
Show the formation of Na2O by the transfer of electrons.
Balance the following equation:
P + HNO3 → NO2 + H2O + H3PO4
Write the balanced chemical equation of the following reaction.
potassium dichromate + hydrochloric acid → Potassium chloride + chromium chloride + water + chlorine
Write word equation for the following molecular equation:
\[\ce{CaCO3 + 2HCl ->[\triangle] CaCl2 + H2O + CO2 [g]}\]
Word equation:
State which characteristic does [g] in the above reaction indicate. The word equation of:
In certain reaction an insoluble solid called precipitate is formed. State the colour and name of the precipitate formed in the following reaction involving addition of:
Dilute hydrochloric acid to silver nitrate.
Explain the term ‘chemical equation’.
Balance the following simple equation:
\[\ce{N2 + H2 <=> NH3}\]
CaCO3 + 2HCl[dil.] → CaCl2 + H2O + CO2 [g]
State the information not conveyed by the above chemical equation.
What are reactants? Explain with the help of example.
Balance the given chemical reaction as per the instructions below.
\[\ce{NaOH + H2SO4 -> Na2SO4 + H2O}\]
Make a list of the elements in the chemical equation.
The following reaction is an example of a `4"NH"_3("g") + "SO"_2 -> 4"NO"("g") + 6"H"_2"O"("g")`
- displacement reaction
- combination reaction
- redox reaction
- neutralisation reaction
What is a reactant in a chemical equation?
