What was the test or tests that made you decide if you compound was an aldehyde or a ketone and why?

Tollen's test or silver mirror test is use to distinguish between ketone and aldehyde.

Explanation:

Tollen's test is use to distinguish aldehyde from ketone because Tollen reagent consist of silver nitrate and ammonia and it oxidized aldehydes to carboxylic acid and the silver Ag+ is reduced to solid silver Ag. It form a inner film wall on the tube that look like mirror. Ketone do not react with Tollen reagent and therefore does not form silver mirror on the tube wall.

answer; talc and gypsum;