Question

Balance each of the following redox reactions and classify it as a combination, decomposition, or displacement reaction:

$\left(a\right)HI\left(g\right)\to H_2\left(g\right)+I_2\left(g\right)$

$\left(b\right)Zn\left(s\right)+AgN{O}_3\left(aq\right)\to Zn{\left(N{O}_3\right)}_2\left(aq\right)+Ag\left(s\right)$

$\left(c\right)NO\left(g\right)+O_2\left(g\right)\to N_2{O}_4\left(l\right)$

Short answer

The classifications of the given reactions are:

(a) Decomposition reaction

(b) Displacement reaction

(c) Combination reaction

Step-by-step solution

Write balanced reaction of equation (a)

The given reaction is:

$HI\left(g\right)\to H_2\left(g\right)+I_2\left(g\right)$

The balanced reaction is:

$2HI\left(g\right)\to H_2\left(g\right)+I_2\left(g\right)$

The given redox reaction is a decomposition reaction.

In this reaction, HI decomposes and forms$H_2$and$I_2.$

Write balanced reaction of equation (b)

The given reaction is:

$Zn\left(s\right)+AgN{O}_3\left(aq\right)\to Zn{\left(N{O}_3\right)}_2\left(aq\right)+Ag\left(s\right)$

The balanced reaction is:

$Zn\left(s\right)+2AgN{O}_3\left(aq\right)\to Zn{\left(N{O}_3\right)}_2\left(aq\right)+2Ag\left(s\right)$

The given redox reaction is a displacement reaction.

The zinc atom replaces silver atom from$AgN{O}_3$ and forms $Zn{\left(N{O}_3\right)}_2.$

Write balanced reaction of equation (c) 

The given reaction is:

$NO\left(g\right)+O_2\left(g\right)\to N_2{O}_4\left(l\right)$

The balanced reaction is:

$2NO\left(g\right)+O_2\left(g\right)\to N_2{O}_4\left(l\right)$

The given redox reaction is a combination reaction.

In this reaction, NO andO₂combines and formsN₂O_4.