Question

The first and second ionization enthalpies of metal are $496$ and $4560\mathrm{kJ}{\mathrm{mol}}^{-1}$ respectively. How many moles of $\mathrm{HCl}$ and ${\mathrm{H}}_2{\mathrm{SO}}_4$, respectively, will be needed to react completely with 1 mole of metal hydroxide?

• A. 1 and 2
• B. 1 and 0.5
• C. 1 and 1
• D. 2 and 0.5

Answer 1

The correct option is B

1 and 0.5

Explanation of the correct option:

The correct answer is option B:

1. The ionization energy statistics provided clearly demonstrate that ${\mathrm{IE}}_2\gg {\mathrm{IE}}_1$.
2. As a result, the element is a member of group 1.
3. As a result, we may infer that this element is monovalent and hence creates a monoacidic base of type $\mathrm{MOH}$.

$$\begin{gathered} \mathrm{MOH}+\mathrm{HCl}\to \mathrm{MCl}+{\mathrm{H}}_2\mathrm{O} \\ 2\mathrm{MOH}+{\mathrm{H}}_2{\mathrm{SO}}_4\to {\mathrm{M}}_2{\mathrm{SO}}_4+2{\mathrm{H}}_2\mathrm{O} \end{gathered}$$

Therefore, based on the equation above, we may infer that 0.5 moles of ${\mathrm{H}}_2{\mathrm{SO}}_4$ and 1 mole of HCl are needed for every mole of metal hydroxide.

Hence, 1 and 0.5 moles of $\mathrm{HCl}$ and ${\mathrm{H}}_2{\mathrm{SO}}_4$, respectively, will be needed to react completely with 1 mole of metal hydroxide.