Which pair of substances would most likely result in the production of a solid when reacting with a base? litmus and phenolphthalein soluble metal salt and carbon dioxide acids and water hydrogen ions and soaps

Answer;

Soluble metal salt and carbon dioxide

Explanation;

Both soluble metal salt and carbon dioxide may react with a base to form a solid or what we call a precipitate.

For instance when carbon dioxide is bubbled through a solution of calcium hydroxide, it results to the formation or precipitate calcium carbonate.

Ca(OH)₂(aq) + CO₂(g) → CaCO₃(s) + H₂O(l)

For the case of a soluble metal salt; an example is calcium nitrate, which is a soluble metal salt, when reacted with a base like sodium hydroxide, it results to the formation of a solid calcium hydroxide and sodium nitrate, a reaction called precipitation reaction.

Ca(NO₃)₂(aq) + NaOH (aq)→ Ca(OH)₂(s) + NaNO₃(aq)

The answer is 65.3312