Question

write a chemical equations of the reaction in which the following changes have taken place with an example of each
(a) change in colour
(b) change in temperature
(c) formation of precipitate ​

Answer 1

Answer:

Explanation:

Change in colour .

potassium dichromate solution and sulphur dioxide are characterised by change in colour from Orange to green.

Change in temperature =

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).

Answer 2

Answer:

1. The chemical reaction between citric acid and purple coloured potassium permanganate solution is characterised by change in colour (from purple to colourless).

2. The reaction between quick lime and water to form slaked lime is characterised by a change in temperature.Ca + 2H2O > Ca(OH)2 + H2 3.na2so4+bacl=baso4+nacl