Any units will do. for example, let's use the unit of "dozens":

2 dozen of h2 particles + _(1, 2, or dozen of o2 particles → _(1, 2, or 3)_ dozen water particles

2 dozen of H₂ particles  + 1 dozen of O₂ particles  → 2 dozen of H₂O particles.

Explanation:

2H₂ + O₂ → 2H₂O.

So, every 2.0 moles of H₂ react with 1.0 mole of O₂ to produce 2.0 moles of H₂O.

So, the represented reaction of the problem is:

2 dozen of H₂ particles  + 1 dozen of O₂ particles  → 2 dozen of H₂O particles.

i believe it is-

d.) gravity pulled particles of dust and gas together to form planets.

the correct answer is b. a strong acid completely dissociates to its ions when dissolved in water. completely dissociates to and ions. a is incorrect because does not fully ionize to and ions and some remain as the compound . c and d are incorrect because, and do not fall into the category of bronsted lowry acids. a bronsted lowry acid is a proton donor and since both molecules do not have a proton to donate they are not bronsted lowry acids. likewise,   if we use the lewis acid definition, they cannot be acids. a lewis acid is an electron pair acceptor. both and have a complete octet so can not accept any electrons which disqualifies them as acids.