The selected acids and bases for the neutralization reactions are:
(a) Acid: Hydrobromic acid (HBr)
Base: Potassium hydroxide (KOH)
Balanced equation: HBr + KOH → KBr + H₂O
(b) Acid: Nitrous acid (HNO₂)
Base: Zinc hydroxide (Zn(OH)₂)
Balanced equation: 2 HNO₂ + Zn(OH)₂ → Zn(NO₂)₂ + 2 H₂O
(c) Acid: Hydrocyanic acid (HCN)
Base: Calcium hydroxide (Ca(OH)₂)
Balanced equation: 2 HCN + Ca(OH)₂ → Ca(CN)₂ + 2 H₂O
(d) Acid: Phosphoric acid (H₃PO₄)
Base: Potassium hydroxide (KOH)
Balanced equation: 2 H₃PO₄ + 6 KOH → 2 K₃PO₄ + 6 H₂O
In order to select an acid and a base for a neutralization reaction that results in the formation of the given compounds, we need to identify the corresponding ions in each compound and match them with appropriate acids and bases.
(a) For the formation of potassium bromide (KBr), we need an acid that will provide the bromide ion (Br⁻) and a base that will provide the potassium ion (K⁺). An example of an acid that can provide the bromide ion is hydrobromic acid (HBr), and an example of a base that can provide the potassium ion is potassium hydroxide (KOH). The balanced equation for this reaction is:
HBr + KOH → KBr + H₂O
(b) For the formation of zinc nitrite (Zn(NO₂)₂), we need an acid that will provide the nitrite ion (NO₂⁻) and a base that will provide the zinc ion (Zn²⁺). An example of an acid that can provide the nitrite ion is nitrous acid (HNO₂), and an example of a base that can provide the zinc ion is zinc hydroxide (Zn(OH)₂). The balanced equation for this reaction is:
2 HNO₂ + Zn(OH)₂ → Zn(NO₂)₂ + 2 H₂O
(c) For the formation of calcium cyanide (Ca(CN)₂), we need an acid that will provide the cyanide ion (CN⁻) and a base that will provide the calcium ion (Ca²⁺). An example of an acid that can provide the cyanide ion is hydrocyanic acid (HCN), and an example of a base that can provide the calcium ion is calcium hydroxide (Ca(OH)₂). The balanced equation for this reaction is:
2 HCN + Ca(OH)₂ → Ca(CN)₂ + 2 H₂O
(d) For the formation of potassium phosphate (K₃PO₄), we need an acid that will provide the phosphate ion (PO₄³⁻) and a base that will provide the potassium ion (K⁺). An example of an acid that can provide the phosphate ion is phosphoric acid (H₃PO₄), and an example of a base that can provide the potassium ion is potassium hydroxide (KOH). The balanced equation for this reaction is:
2 H₃PO₄ + 6 KOH → 2 K₃PO₄ + 6 H₂O