Question

Which of the following reactions occurs most rapidly at room temperature?

a.2AgNO3(aq) + Na2CrO4(aq) → Ag2CrO4(s) + 2NaNO3(aq)

b.CaO(s) + 3C(s) → CaC2(s) + CO(g)

c.SnO2(s) + 2CO(g) → Sn(s) + 2CO2(g)

d.2Fe(s) + O2(g) → 2FeO(s)

Answer 1

The correct option is A.

Looking at the options given above, you will notice that the physical states of the chemical compounds were given in the chemical equations. The reaction in option A is the one that will occur most rapidly because the two reactants involved in the reaction are both in liquid state. Reaction of compounds that are in solid state is comparatively slower because of reduced surface area.

Answer 2

I think the correct answer from the choices listed above is option A. The reaction that occurs most rapidly at room temperature would be 2AgNO3(aq) + Na2CrO4(aq) → Ag2CrO4(s) + 2NaNO3(aq). This is an ionic reaction involving simple exchange of ions in a solution after which the insoluble silver chromate precipitates down.