Q21E - Chemistry (OpenStax)

Question

Complete and balance the following acid-base equations:

(a)HCl gas reacts with solidCa(OH)₂

(b) A solution of Sr(OH)₂  is added to a solution ofHNO_3.

Step-by-Step Solution

Answer

(a)\(2HCl\left( g \right) + Ca{\left( {OH} \right)_2} \to CaC{l_2}\left( {aq} \right) + 2{H_2}O\left( l \right)\)

(b)\(Sr{\left( {OH} \right)_2}\left( {aq} \right) + 2HN{O_3}\left( {aq} \right) \to Sr{\left( {N{O_3}} \right)_2}\left( {aq} \right) + 2{H_2}O\left( l \right)\)

Step 1: Formation of calcium chloride salt

For anacid-base reaction, the products are salt and water.

First balance the calcium atoms, and then the chloride atoms, followed by the hydrogen and oxygen atoms.

\(2HCl\left( g \right) + Ca{\left( {OH} \right)_2} \to CaC{l_2}\left( {aq} \right) + 2{H_2}O\left( l \right)\)

Use the balancing table to check:

Element	Reactant	Product	Balanced? yes
Ca	1x1	1x1	1=1
Cl	2x1	1x2	2=2
H	2x1+1x2	2x2	4=4
O	1x2	2x1	2=2

Step 2: Formation of strontium nitrate salt

First balance the strontium atoms and the nitrate ions, followed by the hydrogen and oxygen atoms.

\(Sr{\left( {OH} \right)_2}\left( {aq} \right) + 2HN{O_3}\left( {aq} \right) \to Sr{\left( {N{O_3}} \right)_2}\left( {aq} \right) + 2{H_2}O\left( l \right)\)

Use the balancing table to check:

Element	Reactant	Product	Balanced? yes
Sr	1x1	1x1	1=1
N	2x1	1x2	2=2
H	1x2+2x1	2x2	4=4
O	1x2+2x3	1x6+2x1	8=8