Question

The following questions refer to the chemical reactions represented below. (A) 2 C6H6(l) + 15 O2(g) → 12 CO2(g) + 6 H2O(l)(B) C2H3O2-(aq) + H3O+(aq) → HC2H3O2(aq) + H2O(l)(C) 4 H+(aq) + 4 Co2+(aq) + O2(g) + 24 NH3(aq) → 4 Co(NH3)63+(aq) + 2 H2O(l)(D) CaCO3(s) → CaO(s) + CO2(g)(E) 2 H2O2(l) → O2(g) + 2 H2O(l)The reaction between a Brønsted-Lowry acid and a Brønsted-Lowry base

Answer 1

Only reaction (B) involving the acetate ion and hydronium ion represents a Brønsted-Lowry acid-base reaction, where the acetate ion acts as a base by accepting a proton from the hydronium ion.

A Brønsted-Lowry acid is defined as a substance that can donate a proton (H+ ion), while a Brønsted-Lowry base is a substance that can accept a proton. In these reactions:

(A)
`\(2\text{C}_6\text{H}_6(\ell) + 15\text{O}_2(g) \rightarrow 12\text{CO}_2(g) + 6\text{H}_2\text{O}(\ell)\)`

There are no
`H^+` ions being transferred; it's a combustion reaction.

(B)
`\(\text{C}_2\text{H}_3\text{O}_2^-(aq) + \text{H}_3\text{O}^+(aq) \rightarrow \text{HC}_2\text{H}_3\text{O}_2(aq) + \text{H}_2\text{O}(\ell)\)`

This is an acid-base reaction where the acetate ion (
`C_2H_3O_2^-`) accepts a proton from hydronium ion (
`H_3O^+`).

(C)
`\(4\text{H}^+(aq) + 4\text{Co}^(2+)(aq) + \text{O}_2(g) + 24\text{NH}_3(aq) \rightarrow 4\text{Co(NH}_3)_6^(3+)(aq) + 2\text{H}_2\text{O}(\ell)\)`

Here, ammonia (
`NH_3`) acts as a base, accepting protons from both
`H^+` and
`CO^(2)` ions.

(D)
`\(\text{CaCO}_3(s) \rightarrow \text{CaO}(s) + \text{CO}_2(g)\)`

This is a decomposition reaction where calcium carbonate loses a proton and forms calcium oxide and carbon dioxide.

(E)
`\(2\text{H}_2\text{O}_2(\ell) \rightarrow \text{O}_2(g) + 2\text{H}_2\text{O}(\ell)\)`

It is a decomposition reaction where hydrogen peroxide loses a proton to form oxygen gas and water.