Answer : The correct option is, (D) [tex]Mg(s)+2HCl(aq)\rightarrow MgCl_2(s)+H_2(g)[/tex]
Explanation :
(A) [tex]AgNO_3(aq)+NaCl(aq)\rightarrow AgCl(s)+NaNO_3(aq)[/tex]
This reaction is a double displacement reaction in which the cation and anion of two reactants are exchange their places to give two different products.
(B) [tex]H_2CO_3(aq)\rightarrow H_2O(l)+CO_2(g)[/tex]
This reaction is a decomposition reaction in which the larger molecule decomposes to give two or more products.
(C) [tex]NaOH(aq)+HCl(aq)\rightarrow NaCl(s)+H_2O(aq)[/tex]
This reaction is a neutralization reaction in which an acid and a base react to give a salt and water as a product.
(D) [tex]Mg(s)+2HCl(aq)\rightarrow MgCl_2(s)+H_2(g)[/tex]
This reaction is a redox reaction in which the oxidation and reduction reaction occur simultaneously.
Oxidation reaction is the reaction in which a substance looses its electrons. In this oxidation state increases.
Reduction reaction is the reaction in which a substance gains electrons. In this oxidation state decreases.
In this reaction, magnesium shows oxidation due to change in oxidation number from (0) to (+2) and hydrogen shows reduction due to change in oxidation number from (-1) to (0).
Hence, the correct option is, (D)
