Final answer:
A) Precipitation. A white smoky-like precipitate in the test tube indicates a precipitation reaction is occurring, typically when a salt solution reacts with silver nitrate to form an insoluble silver halide solid.
Step-by-step explanation:
The reaction occurring in the test tube is a precipitation reaction. When clear liquid, presumably a salt solution, is mixed with silver nitrate, a reaction takes place where the observable result is the formation of a white, smoky-like precipitate within the liquid.
Precipitation reaction refers to the formation of a solid in a solution during a chemical reaction.
When ionic compounds are mixed in solution, the ions can react to form a new substance that is insoluble in water, known as a precipitate.
The balanced equation for the reaction would depend on the salt in the original solution.
However, since a pale yellow precipitate forms upon addition of silver nitrate, a common reaction is that between a halide salt and silver nitrate, where the precipitate would be silver halide.
For example, if the original salt was a chloride, the reaction with silver nitrate would be:
NaCl (aq) + AgNO₃ (aq) → AgCl (s) + NaNO₃ (aq)
Here, AgCl is the white, smoky precipitate and NaNO₃ is the remaining aqueous solution.