Question

27 soit la réaction suivante:
mg$_{(s)}$ + 2 hcl$_{(aq)}$ $\
ightarrow$ mgcl$_2$$_{(aq)}$ + h$_2$$_{(g)}$
quel est le volume dune solution dacide chlorhydrique à 2,5 mol/l qui est nécessaire pour faire réagir complètement 5,00 g de magnésium ?

Explanation:

Step1: Calculate moles of Mg

Molar mass of Mg is \( 24.305 \, \text{g/mol} \). Moles of Mg: \( n_{\text{Mg}} = \frac{m_{\text{Mg}}}{M_{\text{Mg}}} = \frac{5.00 \, \text{g}}{24.305 \, \text{g/mol}} \approx 0.2057 \, \text{mol} \)

Step2: Relate moles of Mg and HCl

From reaction: \( 1 \, \text{mol Mg} \) reacts with \( 2 \, \text{mol HCl} \). So moles of HCl: \( n_{\text{HCl}} = 2 \times n_{\text{Mg}} = 2 \times 0.2057 \, \text{mol} = 0.4114 \, \text{mol} \)

Step3: Calculate volume of HCl solution

Molarity \( M = \frac{n}{V} \), so \( V = \frac{n}{M} \). \( V_{\text{HCl}} = \frac{0.4114 \, \text{mol}}{2.5 \, \text{mol/L}} = 0.16456 \, \text{L} = 164.56 \, \text{mL} \approx 0.165 \, \text{L} \) (or 165 mL)

Answer:

The volume of HCl solution is approximately \( 0.165 \, \text{L} \) (or \( 165 \, \text{mL} \))