Question

In which of the following reactions is mass and/or

charge not conserved?
A) H₂O → H+ + OH-
B) CIO2 + 2 H2O + 4e → Cl- + 4 OH-
C) H2SO4 + NaOH → Na2SO4 + H+ + 2 OH-
D) ZnCl + H₂O → ZnOH + H+ + Cl−
E) none of the above

Answer 1

The answer is E) none of the above.

In all of the given reactions, mass and charge are conserved. The law of conservation of mass states that the mass of reactants must be equal to the mass of the products in a chemical reaction. The law of conservation of charge states that the total charge of the reactants must be equal to the total charge of the products.

In reaction A, the water molecule dissociates into a hydrogen ion (H+) and a hydroxide ion (OH-), but the total mass and charge are still conserved.

In reaction B, the reduction of CIO2 to Cl- is balanced by the oxidation of water to form OH-. The electrons and charge are conserved.

In reaction C, H2SO4 reacts with NaOH to form Na2SO4, H+ and OH-. The mass and charge are conserved.

In reaction D, ZnCl reacts with water to form ZnOH, H+ and Cl-. The mass and charge are also conserved.