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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
Give one example of a chemical reaction.
When hydrogen is passed over copper oxide, copper and steam are formed. Write a balanced equation for this reaction and state which of the chemicals are elements.
With the help of an appropriate example, justify that some of the chemical reactions are determined by Change in temperature.
Give chemical equation for the reaction involved in the above case.
One of the following does not happen during a chemical reaction. This is:
(a) Breaking of old chemical bonds and formation of new chemical bonds
(b) Formation of new substances with entirely different properties
(c) Atoms of one element change into those of another element to form new products.
(d) A rearrangement of atoms takes place to form new products.
One of the following is an exothermic reaction. This is:
(a) electrolysis of water
(b) conversion of limestone into quicklime
(c) process of respiration
(d) process of photosynthesis
Name the various types of chemical reactions.
Write word equation for the following skeletal equation:
\[\ce{FeCl2 + Cl2 -> FeCl3}\]
Write down what you understood from the following chemical reaction.
AgNO3(aq) + NaCI(aq) → AgCI ↓ + NaNO3(aq)
Write the balanced chemical equation of the following reaction.
silver nitrate → silver + nitrogen dioxide + oxygen
Write the balanced chemical equation of the following reaction.
iron pyrites(FeS2) + oxygen → ferric oxide + sulphur dioxide
\[\ce{MnO2 + 4HCl -> MnCl2 + 2H2O + Cl2}\]
0.02 moles of pure MnO2 is heated strongly with conc. HCl. Calculate the mass of salt formed.
1 g of copper powder was taken in a China dish and heated. What change takes place on heating? When hydrogen gas is passed over this heated substance, a visible change is seen in it. Give the chemical equations of reactions, the name and the color of the products formed in each case.
Write word equation for the following molecular equation:
\[\ce{NH3 [g] + HCl [g] ⇌ NH4Cl [s]}\]
Word equation:
State which characteristic is observed in the above reaction.
Give an-example of a similar above characteristic, seen between two other gaseous reactants.
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 – copper carbonate.
Balance the following simple equation:
Fe + Cl2 → FeCl3
Balance the following simple equation:
Fe + H2O ⇌ Fe3O4 + H2
Balance the following simple equation:
Al + H2SO4 → Al2(SO4)3 + H2
Write a balanced equation for the following word equation:
Potassium nitrate → Potassium nitrite + Oxygen
Complete the given chemical reaction.
\[\ce{CuSO_{4(aq)} + Fe_{(s)} ->}\]______ + ______
Write scientific reason.
Adding zinc particles to a solution of copper sulphate makes the blue solution colorless.
