Q6 E - Chemistry (OpenStax)

Question

Write a balanced equation describing each of the following chemical reactions.

(a) Solid potassium chlorate, KClO₃ decomposes to form solid potassium chloride and diatomic oxygen gas

(b) Solid aluminium metal reacts with solid diatomic iodine to form solid Al₂I₆

(c) When solid sodium chloride is added to aqueous sulfuric acid, hydrogen chloride gas and aqueous sodium sulfate are produced.

(d) Aqueous solutions of phosphoric acid and potassium hydroxide react to produce aqueous potassium dihydrogen phosphate and liquid water.

Step-by-Step Solution

Answer

The balanced equations for the chemical reactions are as follows:

(a) \(2KCl{O_3}\left( s \right) \to 2KCl\left( s \right) + 3{O_2}\left( g \right)\)

(b) \(2Al\left( s \right) + 3{I_2}\left( s \right) \to A{l_2}{I_6}\left( s \right)\)

(c) \(2NaCl\left( s \right) + {H_2}S{O_4}(aq) \to 2HCl\left( g \right) + N{a_2}S{O_4}\left( {aq} \right)\)

(d) \({H_3}P{O_4}\left( {aq} \right) + KOH\left( {aq} \right) \to K{H_2}P{O_4}\left( {aq} \right) + {H_2}O\left( l \right)\)

Step 1: Balanced equation for decomposition of potassium chlorate

The balanced equation is as represented below:

\(2KCl{O_3}\left( s \right) \to 2KCl\left( s \right) + 3{O_2}\left( g \right)\)

Draw the balancing table using the coefficients and subscripts of the formulae.

Element	Reactant	Product	Balanced? yes
K	2×1	2×1	2=2
Cl	2×1	2×1	2=2
O	2×3	3×2	6=6

Step 2: Balanced equation for reaction of aluminium with iodine

The balanced equation is as represented below:

\(2Al\left( s \right) + 3{I_2}\left( s \right) \to A{l_2}{I_6}\left( s \right)\)

Draw the balancing table using the coefficients and subscripts of the reaction formulae.

Element	Reactant	Product	Balanced? yes
Al	2×1	1×2	2=2
I	3×2	1×6	6=6

Step 3: Balanced equation for reaction of sodium chloride with sulfuric acid

The balanced reaction is as given below:

\(2NaCl\left( s \right) + {H_2}S{O_4}(aq) \to 2HCl\left( g \right) + N{a_2}S{O_4}\left( {aq} \right)\)

Draw the balancing table using the coefficients and subscripts of the reaction formulae.

Element	Reactant	Product	Balanced? yes
Na	2×1	1×2	2=2
Cl	2×1	2×1	2=2
S	1×1	1×1	1=1
H	1×2	2×1	2=2
O	1×4	1×4	4=4

Step 4: Balanced equation for reaction of phosphoric acid with potassium hydroxide

The balanced reaction is as given below:

\({H_3}P{O_4}\left( {aq} \right) + KOH\left( {aq} \right) \to K{H_2}P{O_4}\left( {aq} \right) + {H_2}O\left( l \right)\)

Draw the balancing table using the coefficients and subscripts of the reaction formulae.

Element	Reactant	Product	Balanced? yes
K	1×1	1×1	1=1
P	1×1	1×1	1=1
H	1×3+1×1	1×2+1×2	4=4
O	1×4+1×1	1×4+1×1	5=5