Question

Write chemical eqn.for..
change in colour
change in temperature
formation of precipitate

Answer 1

heya!!

here is ur answer ........
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◆change in colour .
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potassium dichromate solution and sulphur dioxide are characterised by change in colour from Orange to green.

◆Change in temperature
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chemical reaction between quicklime and water is characterised by change in temperature

●CaCO3(s)+Heat-----------)Hai(s)+CO2(g)

◆formation of precipitate
–-------------------------------------
Ca(OH)2(aq)+CO2---------;-)CaCO3(s)【precipitate】+H2O(I)


hope it help you ☺

Answer 2

Answer:

1. Change in colour :

The reaction between lead nitrate solution and poassium iodide solution.

Chemical equation as follow :

Pb ( NO₃ )₂ + 2 KI  ⇒  PbI₂ + 2 KNO₃

In above reaction colour change from colourless to yellow.

2. Change in temperature :

The reaction between dil. sulphuric acid on zinc.

Chemically :

Zn + H₂SO₄  ⇒  ZnSO₄ + H₂

Heat evolved in the above reaction.

3. Formation of precipitation​ :

The reaction between barium chloride on sodium sulphate.

Chemically :

BaCl₂ + Na₂SO₄  ⇒  BaSO₄ + 2 NaCl

In the above reaction white ppt. of BaSO₄ will form.