Question

(THIS QUESTION IS FROM APEX IN COURSE: Physical Science Sem 2

Which of the following are double-displacement reactions?
Check all that apply.

A. HC2H3O2(aq) + NaHCO3(aq) → NaC2H3O2(aq) + H2CO3(aq)

B. NaOH(aq) + HCI(aq) → NaCI(aq) + HOH(I)

C. Zn (s) + HCI (aq) → ZnCI2 (aq) + H2 (g)

D. 2Cu (s) + O2 (g) → 2CuO (s)

Answer 1

The following double-displacement reactions are fully applied/answered:

A. HC2H3O2(aq) + NaHCO3(aq) → NaC2H3O2(aq) + H2CO3(aq)

B. NaOH(aq) + HCI(aq) → NaCI(aq) + HOH(I)

(The answers are A. & B.)

Answer 2

Answer: The correct answer is Option A and Option B.

Explanation:

Double displacement reaction is defined as the chemical reaction in which exchange of ions takes place.

The general equation for this reaction follows:

$AB+CD\rightarrow CB+AD$

For the given options:

Option A:  $HC_2H_3O_2(aq.)+NaHCO_3(aq.)\rightarrow NaC_2H_3O_2(aq.)+H_2CO_3(aq.)$

This is considered as a double displacement reaction.

Option B:  $NaOH(aq.)+HCl(aq.)\rightarrow NaCl(aq.)+HOH(l)$

This is considered as a double displacement reaction.

Option C:  $Zn(s)+HCl(aq.)\rightarrow ZnCl_2(aq.)+H_2(g)$

This is considered as a single displacement reaction because more reactive metal (zinc) is displacing a less reactive metal (hydrogen).

Option D:  $2Cu(s)+O_2(g)\rightarrow 2CuO(s)$

This is considered as a synthesis reaction because copper and oxygen are combining in their elemental state to produce a single compound.

Hence, the correct answer is Option A and Option B.