Question

How can we determine that a chemical reaction has taken place if no macroscopic change is observable?

Answer 1

The following can indicate that a chemical change has taken place, although this evidence is not conclusive: Change of odor. Change of color (for example, silver to reddish-brown when iron rusts). Change in temperature or energy, such as the production (exothermic) or loss (endothermic) of heat.

Answer 2

Answer:

i) CHANGE IN COLOURS

ii) CHANGE IN ODOUR

iii) CHANGE IN TEMPERATURE