Question

The enthalpies of solution of $Ba{Cl}_2\left(s\right)$ and $Ba{Cl}_2.2H_{2}O\left(s\right)$ are $-20.6$ and $8.8kJ$ ${mol}^{-1}$, respectively. The enthalpy change for the reaction is:

• A. $-29.8kJ$
• B. $-11.8kJ$
• C. $-20.6kJ$
• D. $-29.4kJ$

Answer 1

The correct option is A $-29.8kJ$

$Ba{Cl}_2\left(s\right)+2H_{2}O\left(l\right)⟶Ba{Cl}_2.2H_{2}O\left(s\right)$

Enthalpy change for the reaction = Enthalpy of solution of ${BaCl}_2\left(s\right)$ $-$ Enthalpy of solution of ${BaCl}_2.2H_{2}O\left(s\right)$

$=(-20.6-8.8)KJ/mol$

$=-29.8KJ/mol$