Functional Group Tests -- Procedures?

Question

A chemistry student prepares the Tollens reagent by adding 1mL of aqueous silver nitrate solution and 1mL of 10% NaOH solution.
Then he adds 10mL of 10% ammonia solution and the precipitate dissolves.
After adding 3 drops of unknown, no silver mirror is formed.
What does that result indicate?

Select the best explanation from those shown.

a. To test properly, the solution would have to be heated.
b. A precipitate will NOT form if too much ammonia is added.
c. The wrong solutions were used to prepare the reagent.
d. The solution was prepared correctly and the unknown is NOT an aldehyde.

Answer 1

Both A and D are correct. The Tollens test needs to be warmed and if the test in negative there is no aldehyde present.

Answer 2

d.