for #1 - If it's not magnetic that rules out iron, steel or plated steel (galvanized).
for #3 - HCL would cause it to make Hydrogen gas bubbles.
What are you trying to say with #2?
Aluminum will react with Sodium Hydroxide in the way you describe. Is it a regular sized piece of metal, like a bar or plate? If so then calculate the volume and weigh it. Then divide weight in pounds by the volume in cubic inches. Do it accurately and report the value to 3 decimal places. Aluminum is 0.095 LB/cu in (2.643 gm/cc) and Zinc is 0.255 LB/cu in (7.049 gm/cc). As you can see zinc is much denser than aluminum. You may also have an alloy of these two or even some other material like white Tombasil or Nickel silver, etc.