Advertisements
Advertisements
Questions
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
Solution
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
RELATED QUESTIONS
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.
Balance the following equation:
\[\ce{HNO3 + Ca(OH)2 -> Ca(NO3)2 + H2O}\]
Explain, with an example, how the physical states of the reactants and products can be shown in a chemical equation.
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.
Balance the following chemical equation:
\[\ce{MnO2 + HCl -> MnCl2 + Cl2 + H2O}\]
Write the balanced equation for the following reaction, and add the state symbol:
Magnesium carbonate reacts with hydrochloric acid to produce magnesium chloride, carbon dioxide and water.
The chemical reaction between two substances is characterised by a change in colour from orange to green. These two substances are most likely to be:
(a) potassium dichromate solution and sulphur dioxide
(b) potassium permanganate solution and sulphur dioxide
(c) potassium permanganate solution and lemon juice
(d) potassium dichromate solution and carbon dioxide.
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
What happens when silver nitrate solution is added to sodium chloride solution?
Write the equation for the reaction which takes place.
Write the balanced equation for the following chemical reaction.
\[\ce{Barium chloride + Aluminium sulphate -> Barium sulphate + Aluminium chloride}\]
What is a chemical equation?
Balance the following chemical equation :
FeS + HCl → FeCl2 + H2S
Write symbolic representation for the following word equation and balance them :
Calcium oxide + Water → Calcium hydroxide
Complete the following equation:
CH2 + H5OH `("Hot Conc." H_2SO_4)/`>
Give word equation for the following chemical reaction and give the names of the product formed.
ZnCO3 → ZnO + CO2
Write word equation for the following chemical reaction given below. Also state the observation seen in the case.
Pb(NO3)2 + 2NH4OH → 2NH4N03 + Pb(OH)2↓
With reference to a chemical equation state which of the statements 1 to 5 pertain to A or B.
A: Information provided by a chemical equation.
B: Limitations of a chemical equation.
- The nature of the individual elements.
- The speed of the reaction.
- The state of matter in which the substance is present.
- The completion of the reaction.
- The direction of the reaction.
Underline the compound in the equation given below, it is incorrectly balanced and write the correct balancing for the same.
Cl2 + 2H2O + SO2 → 4HCl + H2SO4
Underline the compound in the equation given below, it is incorrectly balanced and write the correct balancing for the same.
2H2O + 2Cl2 → 2HCl + O2
Which among the following is(are) double displacement reaction(s)?
- `"Pb" + "CuCl"_2 -> "PbCl"_2 + "Cu"`
- `"Na"_2"SO"_4 + "BaCl"_2 -> "BaSO"_4 + 2"NaCl"`
- `"C" + "O"_2 -> "CO"_2`
- `"CH"_4 + 2"O"_2 -> "CO"_2 + 2"H"_2"O"`
