A teacher sketches a particulate-level diagram for an aqueous solution of MgCl₂
CHEMISTRY · Single correct · AP · Chemistry · Properties of Substances and Mixtures · Properties of Substances and Mixtures
Problem
A teacher sketches a particulate-level diagram for an aqueous solution of MgCl₂. In the fixed-volume box, six particles are labeled “Mg⁺,” each surrounded by several water molecules with the H atoms pointed toward the ion. Twelve particles labeled “Cl⁻” are dispersed throughout the box, each with the O atom of nearby water molecules pointed toward the ion. Which statement identifies the MOST significant error in the diagram?
(a) Water molecules are oriented incorrectly around the magnesium ions; the oxygen atoms, not the hydrogen atoms, should face the cations.
(b) The ratio of chloride ions to magnesium ions is incorrect; the diagram should show an equal number of each ion.
(c) The diagram should depict chloride ions paired with magnesium ions as intact MgCl2 formula units rather than separated ions.
(d) Magnesium ions are shown with a +1 charge even though each Mg ion in solution carries a +2 charge.