I need the help of our chemists here..Are there any?

Question

If a few pieces of aluminum shavings will be added to a 3mL of dilute hydrochloric acid solution in a test tube and will be tested for the gas evolved by bringing a flame near the mouth of the test tube, what will happen?
What will be tha gas bubbles evolved? What type of change will take place?

If 1g of ammonium chloride crystals will be added to 5mL of water in a test tube, what can be observed?
If the liquid will be transfer to an evaporating dish and evaporate to dryness and will be cooled not to be overheated, what will be observed to the residue? What changes will the ammonium chloride undergo?

Answer 1

For the first one, the Aluminum will dissolve in the acid and give off Hydrogen gas:

2 Al (s) + 6 HCl (aq) --> 2 AlCl3 (aq) + 3 H2 (g)

The Hydrogen will burn with the Oxygen in the air, giving a pop:

2 H2 + O2 --> 2 H2O

For the second one, the Ammonium chloride will easily dissolve in the water. If heated to dryness it will appear as a white powder. This powder is slightly hygroscopic and will pickup water from the atmosphere very slowly forming white or colorless crystals.

If overheated it will dissociate:

NH4Cl --> NH3 + HCl