<u>Answer:</u>
A. Solution of copper (II) sulfate reacts with solution of sodium hydroxide to produce "copper hydroxide & solution of sodium sulphate".
B. Solid baking soda (sodium hydrogen carbonate or sodium bicarbonate) reacts with solution of hydrochloric acid to produce "carbon dioxide and water".
<u>Explanation:</u>
When CuSO4 is an acid salt while NaOH is a solid base mixed together. This reaction results into a basic copper hydroxide in the form of pale blue precipitate & sodium sulphate, which is a solution of neutral salt. This process is called as both a double displacement and precipitation reaction.
2NaOH + CuSO4 --> Cu(OH)2 + Na2SO4.
Sodium bicarbonate is used as a cleaner, from a "primitive" material to extract any acidic contaminants, for producing a nobler sample. Sodium bicarbonate and acid mixture generates a salt and carbonic acid that breaks down readily into carbon dioxide and water.
NaHCO3 + HCl → NaCl + H2CO. H2CO3 → H2O + CO2(g).
