Question

Which of the following equation does NOT correctly depict the process by which the given solute dissolves in water?

• A. Solid calcium nitrate is added to water to form an aqueous solution.
  $Ca\left(N{O}_3{)}_2\right(s)\to C{a}^{2+}(aq)+2N{O}_3^{-}(aq)$
• B. Magensium hydroxide, a very slightly soluble solid, is dissolved in water.
  $Mg\left(OH{)}_2\right(s)\to M{g}^{2+}(aq)+2O{H}^{-}(aq)$
• C. Surcose, table sugar, $C_{12}{H}_{22}{O}_{11}$m dissolves in water.
  $C_{12}{H}_{22}{O}_{11}\left(s\right)\to C_{12}{H}_{22}{O}_{11}\left(aq\right)$
• D. Phosphoric acid, a weak triprotic acid, dissolves in water.
  $H_{3}P{O}_4\left(l\right)\to 3H^{+}\left(aq\right)+P{O}_4^{3-}\left(aq\right)$

Answer 1

The correct option is D Phosphoric acid, a weak triprotic acid, dissolves in water.

$H_{3}P{O}_4\left(l\right)\to 3H^{+}\left(aq\right)+P{O}_4^{3-}\left(aq\right)$
Since, $H_{3}P{O}_4$ is a triprotic acid but its degree of dissociation is not 100%, so it does not give $3H^{+}$ ion on adding water to it.