Q1. What will be formed when propanone reacted with sodium hydrogensulphite?

Question

There is white precipitate is the resulting solution . Is it sodium carbonate?

Q2. What are the difference in the products bewteen the reaction of ethanal and propanone reacting with 2,4-dinitrophenylhydrazine?
The resulting solution are both yellow and orange precipitate is formed . It seems that there are some different in the shape of precipitate.

Q3. What is the polymer formed when ethanal reacted with sodium hydroxide solution?

Q4. What will be formed when ethanal reacted with acidified dichromate(VI) ?
Why is the resulting solution green ?

Q5. What will be formed when propanone reacted with Fehling's solution?The resulting solution is yellow and green precipitate is formed . Is that precipitate copper carbonate?

Q6.What are the difference in products between the reaction of ethanal and propanone reacting with iodine solution and sodium hydroxide solution ?The resulting solution of ethanal one is orange while the other is very pale yellow or nearly colorless.Both of them give yellow precipitate . Are the precipitates the same?

Q7. Which reagent should i use to test for carbonyl compound?