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प्रश्न
With the help of an appropriate example, justify that some of the chemical reactions are determined by Change in colour
Give chemical equation for the reaction involved in the above case.
Give one example of a chemical reaction characterised by change in colour.
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उत्तर
When sulphur dioxide gas is passed through acidified potassium dichromate solution, orange colour of potassium dichromate solution changes to green colour.
\[\ce{3SO2(g) + K2Cr2O7(aq) + H2SO4(aq)->K2SO4(aq) + Cr2(SO4)3(aq) + H2O(I)}\]
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संबंधित प्रश्न
Balance the following chemical equation.
\[\ce{NaOH + H2SO4 -> Na2SO4 + H2O}\]
Write the balanced chemical equation for the following reaction.
\[\ce{Aluminium + Copper chloride -> Aluminium chloride + Copper}\]
Is Decomposition of calcium carbonate an endothermic reaction or an exothermic reaction?
The chemical reaction between quicklime and water is characterised by:
(a) evolution of hydrogen gas
(b) formation of slaked lime precipitate
(c) change in temperature of mixture
(d) change in colour of the product
A metal X forms a salt XSO4. The salt XSO4 forms a clear solution in water which reacts with sodium hydroxide solution to form a blue precipitate Y. Metal X is used in making electric wire and alloys like brass.
(a) What do you think metal X could be?
(b) Write the name, formula and colour of salt XSO4.
(c) What is the blue precipitate Y?
(d) Write a chemical equation of the reaction which takes place when salt XSO4 reacts with sodium hydroxide solution. Give the state symbols of all the reactants and products which occur in the above equation.
Write your observation for the following chemical reaction and name the product formed:
When sugar is heated.
Balance the following equation. Also name the product formed.
`"Na"+ "H"_2 "O" → "NaOH"+ "H"_2`
Balance the equation stepwise.
Ag(s) + HCl(aq) → AgCl ↓+ H2 ↑
Balance the following equation:
Fe + H2O → Fe3O4 + H2
What is the valency of :
carbon in CH4
Write the balanced chemical equation of the following reaction. iron + sulphuric acid → ferrous sulphate + hydrogen.
\[\ce{MnO2 + 4HCl -> MnCl2 + 2H2O + Cl2}\]
0.02 moles of pure MnO2 is heated strongly with conc. HCl. Calculate moles of salt formed.
Identify the type of reaction taking place of the following case and write the balanced chemical equation of the reaction:
Potassium iodide reacts with lead nitrate to produce potassium nitrate and lead iodide.
Name the substance that is getting oxidised in the thermit process.
In certain reaction a change of state is observed i.e. solid to liquid, liquid to gas etc. – State the change of state of the products – to give the respective reactant.
\[\ce{C +2S -> CS2}\]
Give one example in the case where supplying energy [given below] is necessary for a chemical reaction.
Heat energy
Name the following:
Two gases which react under pressure in presence of a catalyst at elevated temperatures to give a gaseous product.
Explain the term ‘chemical equation’.
Give a balanced equation by the partial equation method, [steps are given below].
Oxidation of Lead [II] Sulphide by Ozone
- Ozone first decomposes to give molecular oxygen & nascent oxygen.
- Nascent oxygen then oxidises lead [II] sulphide to lead [II] sulphate.
Underline the compound in the equation given below, it is incorrectly balanced and write the correct balancing for the same.
C2H5OH + 3O2 → 2CO2 + 2H2O
