give one example each of a chemical reaction chatrizsed by (a)change in colour (b)change in temperature (c)change in state
Answers
i) Evolution of gas--- Reaction between zinc and dilute sulphuric acid
ii) Change in color--- Reaction between citric acid and purple colored potassium permanganate solution gives colourless solution.
iii) Formation of precipitate--- Reaction between potassium iodide and lead nitrate forms a yellow precipitate of lead iodide.
iv) Change in temperature: Reaction between zinc granules and dliute hydrochloric acid.
v) Change in state: Combustion of candle wax is characterized by a change in state from solid to liquid and gas.
tysm....#gozmit
1.Evolution of a gas.
2.Change in colour.
3.Formation of a precipitate.
4.Change in temperature.
5.Change in state.
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ANSWER
1.Evolution of gas:
The chemical reaction between zinc and dilute sulphuric acid is characterized by the evolution of hydrogen gas.
Zn(s)+H2SO4(aq)→ZnSO4 (aq)+H2(g)
2.Change in colour:
The reaction between the lead nitrate solution and potassium iodide solution.
Pb(NO3)2(aq)+2KI→PbI2(s)+2KNO3 (aq)
In this reaction colour changes from colourless to yellow.
3.Formation of precipitate:
The action of Barium Chloride on sodium sulphate.
BaCl2(aq)+Na2SO4 (aq)→BaSO4 (s)+2KNaCl(aq)
4.Change in temperature change in temperature:
The action of dilute sulphuric acid on zinc:
Zn(s)+H2SO4 (aq)→ZnSO4 (s)+H2(g)
In this reaction, heat is evolved.
5.Change in the state:
When the wax is burnt in the form of the wax candle then Water and carbon dioxide are formed. Wax is solid water is a liquid whereas carbon dioxide gas.