<span>Acid is known to be a very strong type of liquid because of it destructive and can wipe almost wipe everything. When it reacts with specific objects, gas is produced. When a metal is poured with acids, it reacts. Salt and hydrogen gas will be produced. Putting an ignited splint in the produced gas when an acid reacts with metal, it fired with a creaky sound, because of the hydrogen produced. </span>
The correct answer is nicotine. It is the main ingredient in a tobacco. Nicotine is an addictive substance thus overuse of the substance will lead to addiction. It acts as a stimulant and a depressant. Tobacco can be dried for smoking and can also be consumed directly.
D- If there is a color change that is indicative to that being a chemical change.
A, B, and C are examples of physical changes.
I believe this nuclide is potassium with the symbol K. Atomic number for an element remains constant no matter how the mass changes. From the periodic table, potassium has an atomic number of 19.