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प्रश्न
With the help of an appropriate example, justify that some of the chemical reactions are determined by a change in colour.
Give a chemical equation for the reaction involved in the above case.
Give one example of a chemical reaction characterised by a change in colour.
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उत्तर
When sulphur dioxide gas is passed through an acidified potassium dichromate solution, the orange colour of the potassium dichromate solution changes to green colour.
\[\ce{3SO2_{(g)} + K2Cr2O7_{(aq)} + H2SO4_{(aq)} -> K2SO4_{(aq)} + Cr2(SO4)3_{(aq)} + H2O_{(l)}}\]
Notes
Students should refer to the answer according to their questions.
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संबंधित प्रश्न
Chemical equations are balanced to satisfy the law of ______.
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 compounds.
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You are given the solution of lead nitrate. In order to obtain a yellow precipitate you should mix with it a solution of:
(a) potassium chloride
(b) potassium nitride
(c) potassium sulphide
(d) potassium iodide
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\[\ce{Barium chloride + Aluminium sulphate -> Barium sulphate + Aluminium chloride}\]
Write word equation for the following skeletal equation:
\[\ce{CO + O2 -> CO2}\]
Balance the following equation. Also name the product formed.
`"Na"+ "H"_2 "O" → "NaOH"+ "H"_2`
Balance the following equation. Also name the product formed.
`"CO" + "O"_2 → " CO"_2`
Balance the equation stepwise.
Ag(s) + HCl(aq) → AgCl ↓+ H2 ↑
Balance the following equation:
H2O + Cl2 → HCl + O2
Write the balanced chemical equation of the following reaction.
ammonia + oxygen → nitric oxide + water
Write the balanced chemical equation of the following reaction.
aluminium carbide + water → aluminium hydroxide + methane
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Write the balanced chemical equation for this reaction.
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:
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\[\ce{2KClO3->[MnO2] 2KCl + 3O2[g] - is a balanced equation.}\]
State why the compound MnO2 is written above the arrow.
Balance the following simple equation:
SO2 + O2 ⇌ SO3
Underline the compound in the equation given below, it is incorrectly balanced and write the correct balancing for the same.
PbO2 +4HCl → PbCl2 + H2O + Cl2
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.
Dil. HCl is added to Zn granules. How will you prove that chemical change has taken place here? Support your response with two arguments.
