Question

List any four observations which help us to determine whether a chemical reaction has taken place

Answer 1

four observations are
1-chamge in state
2.change in odour.
3.evolution of gas
4.production of new production

Answer 2

$\huge{\mathfrak{\underline{Question :}}} \\ \\ \textsf{List four observations that} \\ \textsf{help us to determine whether a} \\ \textsf{chemical reaction has taken place.} \\ \\\huge{\mathfrak{\underline{Answer :}}} \\ \\ \textsf{(i) Evolution of gas} \\ \textsf{(ii) Change in temperature} \\ \textsf{(iii) Change in state} \\ \textsf{(iv) Change in color}$