Aclass is given a demonstration of solution chemistry and solubility equilibria. passage: a 6.57-g sample of niso4•6h2o (molar mass 262.84) is dissolved in enough water to make 50.00 ml of a green solution, and 7.15 g of na2co3•10h2o (molar mass 286.14) is dissolved in enough water to make 50.00 ml of a colorless solution. the two solutions are mixed, and a green precipitate forms. the resulting slurry is divided into two equal portions. to one portion is added an excess of 6 m hcl, which results in the disappearance of the precipitate and a rapid evolution of a gas. to the second portion is added a few milliliters of 6 m nh3. the precipitate dissolves, and a blue solution forms. question: according to the information in the passage, the gas that evolves is: a) sulfur dioxide. b) sulfur trioxide. c) carbon dioxide. d) carbon monoxide.

The gas that evolves must be carbon dioxide.

Explanation:

There is two reactions taking place: first, nickel sulfate reacts with sodium carbonate yielding sodium sulfate and nickel carbonate, which is a green solid. Then nickel carbonate reacts with hydrochloride, yielding nickel chloride, carbon dioxide and water.

1) NiSO4 (aq) + Na2SO4 (aq) = NiCO3 (s) + Na2SO4

2) NiCO3 (s) + 2 HCl (aq) = NiCl2 + CO2 + H2O

nacl or sodium chloride is an ionic compound. this is because an ionic compound pertains to a compound that consists of positively and negatively charged ions. in this case, na (sodium) has a tendency to lose one electron when it reacts with with other atoms, so the resulting sodium ion contains 11 protons and 10 electrons, thus making it positively charged (na+), when chlorine reacts, it usually gains one electron to form an ion called chloride, thus making it negatively charged ( since the ions are oppositely charged, they attract.