Advertisements
Advertisements
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.
Advertisements
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.
APPEARS IN
संबंधित प्रश्न
Translate the following statement into a chemical equation and then balance it.
Barium chloride reacts with aluminium sulphate to give aluminium chloride and a precipitate of barium sulphate.
Write the balanced chemical equation for the following reaction.
\[\ce{Zinc + Silver nitrate -> Zinc nitrate + Silver}\]
Translate the following statement into a chemical equation and then balance the equation:
Barium chloride reacts with zinc sulphate to give zinc chloride and barium sulphate.
Rewrite the following information in the form of a balanced chemical equation:
Magnesium burns in carbon dioxide to form magnesium oxide and carbon.
What is meant by a chemical reaction? Explain with the help of an example.
Write the chemical equation for the following word equation and balance them.
Nitrogen + Oxygen → Nitrogen monoxide
Write the chemical equation for the following word equation and balance them.
Magnesium + Sulphuric acid → Magnesium sulphate + Hydrogen
Balance the following equation:
\[\ce{S + HNO3 -> H2SO4 + NO2 + H2O}\]
What information does the following chemical equation convey?
Zn + H2SO4 → ZnSO4+ H2
Why should an equation be balanced? Explain with the help of a simple equation.
Write the balanced chemical equation of the following reaction.
barium chloride + sulphuric acid → barium sulphate + hydrochloric acid
Write the balanced chemical equation of the following reaction.
zinc sulphide + oxygen → zinc oxide + sulphur dioxide
How is a flame test performed?
Match column A with column B.
| Column A | Column B |
| (a) Blue salt changes to white and then black | (i) Ammonium dichromate |
| (b) Orange coloured compound changes to green. | (ii) Iodine |
| (c) Red compound changes to brown and then yellow. | (iii) Zinc Nitrate |
| (d) White to yellow when hot and white when cold. | (iv) Copper sulphate |
| (e) Violet solid changes to violet vapours. | (v) Red Lead |
Write word equation for the following molecular equation:
FeSO4 + 2NaOH →Na2SO4 + Fe(OH)2 ↓
Word equation:
State why [↓] indication is seen after Fe(OH)2 and not after Na2SO4
Give one example in the case where supplying energy [given below] is necessary for a chemical reaction.
Catalyst
Balance the following simple equation:
H2S + Cl2 → S + HCl
Complete the given chemical reaction.
\[\ce{CuSO_{4(aq)} + Fe_{(s)} ->}\]______ + ______
Give the characteristic tests for the following gases :
- CO2
- SO2
- O2
- H2
What are the steps involved in writing the skeletal equation?
