Question

Which balanced equation represents a redox reaction? a. AgNO3(aq) +NaCl(aq) →AgCl(s) +NaNO3(aq) b. H2CO3(aq) →H2O() + CO2(g) c. NaOH(aq) + HCl(aq) →NaCl(aq) + H2O() d. Mg(s) + 2HCl(aq) →MgCl2(aq) + H2(g)
Can you also explain why for every answer

Answer 1

Answer : The correct option is, (D) $Mg(s)+2HCl(aq)\rightarrow MgCl_2(s)+H_2(g)$

Explanation :

(A) $AgNO_3(aq)+NaCl(aq)\rightarrow AgCl(s)+NaNO_3(aq)$

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) $H_2CO_3(aq)\rightarrow H_2O(l)+CO_2(g)$

This reaction is a decomposition reaction in which the larger molecule decomposes to give two or more products.

(C) $NaOH(aq)+HCl(aq)\rightarrow NaCl(s)+H_2O(aq)$

This reaction is a neutralization reaction in which an acid and a base react to give a salt and water as a product.

(D) $Mg(s)+2HCl(aq)\rightarrow MgCl_2(s)+H_2(g)$

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)