Question

$BaC{l}_2$ dissociates in water to give one $B{a}^{2+}$ ion and two Clions. If concentrated $HCl$ is added to this solution,

• A. $\left[B{a}^{2+}\right]$ increases
• B. $\left[OH\right]$ increases
• C. $\left[B{a}^{2+}\right]$ remains constant
• D. $\left[H^{+}\right]$ decreases
• E. The number of moles of undissociated $BaC{l}_2$ increases

Answer 1

Answer: (E)

The number of moles of undissociated $BaC{l}_2$ increases

The common ion effectis the phenomenon in which the addition of an ion common to two solutes causes precipitation or reduces ionization. In the case of the common ion effect, a reaction can be shifted by adding an ion that is common to both solutes, thus changing the concentration of the ion in solution and shifting the equilibrium of the reaction. The net effect of the common ion is that it reduces the solubility of the solute in the solution. The common ion effect can make insoluble substances more insoluble, so The number of moles of undissociated $Bac{l}_2$ increases.