A student combines pairs of chemicals in separate test-tubes: • excess calcium (s) + water (l) • barium chloride (aq) + strontium hydroxide (aq) • calcium carbonate (s) + excess hydrochloric acid (aq) • magnesium sulfate (aq) + barium nitrate (aq) In how many of the mixtures is a white solid formed?
- A$0$
- B$1$
- C$2$
- D$3$