Question

Give one example of each to show that:
•Heat , light , catalyst is required for chemical reaction to occur
•change in colour shows that reaction has occurred
• formation of precipitate has occurred in a reaction
•liberation of gas takes place in a reaction
•presence of electric current is required for chemical reaction to occur
ANSWER ALL MY QUESTIONS BY GIVING EXAMPLES . DONT GIVE ME A LINK

Answer 1

$$\begin{gathered} 1)CaC{O}_3\stackrel{Heat}{\to }CaO+\hspace{0.17em}C{O}_2(heat\left) \\ 2\right)C{O}_2+\hspace{0.17em}{H}_{2}O\stackrel{Sunlight}{\to }{C}_6{H}_{12}{O}_6(light) \\ 3)2KCl{O}_3\stackrel{Mn{O}_2}{\to }2KCl+3O_2(catalyst\left) \\ 4\right)Fe+CuS{O}_4\to FeS{O}_4+Cu(colourchangedfrombluetogreen) \\ 5)BaC{l}_2+\hspace{0.17em}N{a}_{2}S{O}_4\to BaS{O}_4+2NaCl(precipitate\left) \\ 6\right)Ca+\hspace{0.17em}{H}_{2}S{O}_4\to CaS{O}_4+\hspace{0.17em}{H}_2(gasliberation) \\ 7)2NaC{l}_{aq}\to 2Na+C{l}_2(Electricity) \end{gathered}$$