potassium nitrate reaction with hydrochloric acid?

i recently mixed sugar and potassium nitrate to make a rocket. i ignited the mix and after it was done burning it left a molten pool of what i assume is potassium nitrate. i pored hydrochloric acid on the solidified pool and i produced a large amount of heat and was creating a brown-red gas. the gas was heavier than air because it sank to the bottom. can anyone tell me what this gas was?

Brown-red gas, heavier than air, and produced by a mixture containing nitrate (NO3-) ion...

I am going to guess this gas is nitrogen dioxide (N2O),
Oops. I wrote the wrong formula there. Nitrogen dioxide is NO2 That's one nitrogen atom and two oxygen atoms. 

Also, if you got your fuel mix right, the pool will have been a lot more than just potassium nitrate.
myakka (author)  Kiteman4 years ago
thanks guys. I thought it was chlorine but then I remembered that chlorine was green-yellow.