33. 15 g of magnesium ( Mg ) was reacted with 40 g of HCl to form magnesium chloride \( \left(\mathrm{MgCl}_{2}\right) \) and hydrogen gas as in the following reaction: \( \mathrm{Mg}(\mathrm{s})+2 \mathrm{HCl}(\mathrm{aq}) \rightarrow \mathrm{MgCl}_{2}(\mathrm{aq})+\mathrm{H}_{2}(\mathrm{~g}) \) Calculate the mass in gram \( (\mathrm{g}) \) of \( \mathrm{MgCl}_{2} \) formed \( \begin{array}{llll}\text { A) } 25.7 & \text { C) } 104.8 & 30.7 & \text { D) } 52.2\end{array} \)

3) \( \mathrm{Cr}_{2}\left(\mathrm{SO}_{4}\right)_{3}+\mathrm{KI}+\mathrm{KIO}_{3}+\mathrm{H}_{2} \mathrm{O} \longrightarrow \mathrm{Cr}(\mathrm{OH})_{3}+\mathrm{K}_{2} \mathrm{SO}_{4}+\mathrm{I}_{2} \) \( \begin{array}{l}\text { Semireacción de oxidación } \\ \text { Agente oxidante }\end{array} \)

3) \( \mathrm{Cr}_{2}\left(\mathrm{SO}_{4}\right)_{3}+\mathrm{KI}+\mathrm{KIO}_{3}+\mathrm{H}_{2} \mathrm{O} \longrightarrow \mathrm{Cr}(\mathrm{OH})_{3}+\mathrm{K}_{2} \mathrm{SO}_{4}+\mathrm{I}_{2} \) Semireacción de oxidación Agente oxidante

Balancea por óxido - reducción las ecuaciones siguientes: \( \begin{array}{l}\text { 1) } \mathrm{HNO}_{3}+\mathrm{S} \\ \begin{array}{l}\text { Semireacción de oxidación } \\ \text { Agente oxidante } \longrightarrow\end{array} \\ \mathrm{NO}_{2}+\end{array} \mathrm{H}_{2} \mathrm{SO}_{4}+\mathrm{H}_{2} \mathrm{O} \) \( \begin{array}{l}\text { Semireacción de reducción } \\ \text { Agente reductos }\end{array} \)

33. 15 g of magnesium ( Mg ) was reacted with 40 g of HCl to form magnesium chloride \( \left(\mathrm{MgCl}_{2}\right) \) and hydrogen gas as in the following reaction: \( \mathrm{Mg}(\mathrm{s})+2 \mathrm{HCl}(\mathrm{aq}) \rightarrow \mathrm{MgCl}_{2}(\mathrm{aq})+\mathrm{H}_{2}(\mathrm{~g}) \) Calculate the mass in gram \( (\mathrm{g}) \) of \( \mathrm{MgCl}_{2} \) formed \( \begin{array}{llll}\text { A) } 25.7 & \text { C) } 104.8 & 30.7 & \text { D) } 52.2\end{array} \)

Example: 50. OmL of monoprotic acid solution of unknown concentration is titrated with 0.32 M of NaOH. It takes 24.6 mL of this base to reach the endpoint. What is the molarity of this acid?