A student mixes equimolar aqueous solutions of potassium sulfate and barium chloride. The mixture quickly becomes cloudy as a fine white solid appears and settles. Which inference is most strongly supported by this observation?
a) The two solutions have simply diluted each other; the transient cloudiness will vanish once mixing is complete, so no chemical reaction has occurred.
b) Insoluble potassium chloride has precipitated, making the mixture cloudy.
c) An insoluble compound, BaSO4, has formed, producing a precipitate.
d) Gas bubbles produced during mixing are scattering light, creating the appearance of a precipitate rather than an actual solid forming.