Question

$\Delta S$ for the reaction $MgC{O}_3\left(s\right)\to MgO\left(s\right)+C{O}_2\left(g\right)$ will be:

• A. $0$
• B. $-ve$
• C. $+ve$
• D. $\infty$

Answer 1

The correct option is C $+ve$

The entropy change will be positive for a reaction in which the difference in the number of moles of gaseous products and the number of moles of gaseous reactants is positive.

In the reaction $MgC{O}_3\left(s\right)\to MgO\left(s\right)+C{O}_2\left(g\right)$, the number of moles of gaseous reactants is zero and the number of moles of gaseous products is 1.

Therefore, the difference in the number of moles of gaseous products and the number of moles of gaseous reactants is positive.

Hence, the entropy change is positive.