Question

Chemical reactions may or may not produce a colour change.

• A. True
• B. False

Answer 1

The correct option is A True

Colour change

• Some reactions are characterized by changes in color.
• For example, When zinc metal is dissolved in Copper Sulphate, the blue color of the solution changes to colorless because copper is replaced by zinc, and zinc sulfate is formed.

$\underset{\underset{\left(\mathrm{Grey}\right)}{\mathrm{Zinc}}}{\mathrm{Zn}\left(\mathrm{s}\right)}+\underset{\underset{\left(\mathrm{Blue}\right)}{\mathrm{Copper}\mathrm{Sulphate}}}{{\mathrm{CuSO}}_4\left(\mathrm{aq}\right)}\to \underset{\underset{\left(\mathrm{Colourless}\right)}{\mathrm{Zinc}\mathrm{Sulphate}}}{{\mathrm{ZnSO}}_4\left(\mathrm{aq}\right)}+\underset{\underset{\left(\mathrm{Brown}\right)}{\mathrm{Copper}}}{\mathrm{Cu}\left(\mathrm{s}\right)}$

No color change reactions

• In some chemical reactions, the color change is not observed after the reaction, and the color of the solution remains the same
• For example, When acid reacts with base in a neutralization reaction, no color change is observed.

$\underset{(\mathrm{Colourless}\mathrm{solution})}{\underset{\underset{\left(\mathrm{Base}\right)}{\mathrm{Sodium}\mathrm{Hydroxide}}}{\mathrm{NaOH}\left(\mathrm{aq}\right)}+\underset{\underset{\left(\mathrm{Acid}\right)}{\mathrm{Hydochloric}\mathrm{acid}}}{\mathrm{HCl}\left(\mathrm{aq}\right)}}\to \underset{(\mathrm{Colourless}\mathrm{solution})}{\underset{\underset{\left(\mathrm{Salt}\right)}{\mathrm{Sodium}\mathrm{Chloride}}}{\mathrm{NaCl}\left(\mathrm{aq}\right)}+\underset{\mathrm{Water}}{{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}}$

Hence, Chemical reactions may or may not produce a color change during a chemical reaction.

Thus, the given statement is true.