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Difficulty: MediumAlkali Metals: Sodium Extraction, Properties, and Compounds

Match each sodium compound listed on the left with its corresponding characteristic property, industrial preparation process, or commercial application on the right.

  • Sodium peroxide (Na2O2\text{Na}_2\text{O}_2)Acts as an oxygen generator in closed breathing apparatus by reacting with carbon dioxide
  • Sodium hydroxide (NaOH\text{NaOH})Manufactured industrially by the electrolysis of concentrated brine using a mercury cathode cell
  • Sodium hydrogentrioxocarbonate(IV) (NaHCO3\text{NaHCO}_3)Decomposes thermally at moderate temperatures to release carbon dioxide gas
  • Sodium trioxocarbonate(IV) decahydrate (Na2CO3⋅10H2O\text{Na}_2\text{CO}_3\cdot 10\text{H}_2\text{O})Undergoes efflorescence in dry atmosphere to form a white monohydrate powder

Answer

Sodium peroxide matches with acting as an oxygen generator in breathing apparatus; Sodium hydroxide matches with industrial manufacture via brine electrolysis in a mercury cathode cell; Sodium hydrogentrioxocarbonate(IV) matches with thermal decomposition releasing carbon dioxide gas; Sodium trioxocarbonate(IV) decahydrate matches with efflorescence in dry atmosphere to form a monohydrate powder.
Each sodium compound is paired correctly according to its fundamental chemical behavior or industrial utility: Sodium peroxide reacts with carbon dioxide to regenerate oxygen; Sodium hydroxide is manufactured via the chlor-alkali process in Castner-Kellner mercury cells; Sodium hydrogentrioxocarbonate(IV) undergoes thermal decomposition to release carbon dioxide; and Sodium trioxocarbonate(IV) decahydrate loses hydration water through efflorescence.

Step-by-Step Solution

1
Analyze the chemical property and application of sodium peroxide (Na2O2\text{Na}_2\text{O}_2).
Sodium peroxide reacts with carbon dioxide according to the equation 2Na2O2+2CO2→2Na2CO3+O22\text{Na}_2\text{O}_2 + 2\text{CO}_2 \rightarrow 2\text{Na}_2\text{CO}_3 + \text{O}_2, releasing oxygen gas.
This property makes it effective as an oxygen rebreather component.
2
Identify the industrial preparation method for sodium hydroxide (NaOH\text{NaOH}).
Sodium hydroxide is produced by electrolyzing concentrated brine (NaCl(aq)\text{NaCl}_{(aq)}) in a Castner-Kellner cell containing a mercury cathode.
Sodium ions discharge at the mercury cathode forming an amalgam, which reacts with water to yield pure NaOH\text{NaOH}.
3
Examine the thermal stability of sodium hydrogentrioxocarbonate(IV) (NaHCO3\text{NaHCO}_3).
Heating NaHCO3\text{NaHCO}_3 causes decomposition: 2NaHCO3→ΔNa2CO3+H2O+CO22\text{NaHCO}_3 \xrightarrow{\Delta} \text{Na}_2\text{CO}_3 + \text{H}_2\text{O} + \text{CO}_2.
Alkali metal hydrogentrioxocarbonates decompose upon gentle heating to liberate carbon dioxide gas.
4
Determine the effect of air exposure on hydrated sodium trioxocarbonate(IV) (Na2CO3⋅10H2O\text{Na}_2\text{CO}_3\cdot 10\text{H}_2\text{O}).
Exposure to dry air leads to the loss of nine water molecules: Na2CO3⋅10H2O→Na2CO3⋅H2O+9H2O\text{Na}_2\text{CO}_3\cdot 10\text{H}_2\text{O} \rightarrow \text{Na}_2\text{CO}_3\cdot \text{H}_2\text{O} + 9\text{H}_2\text{O}.
This spontaneous loss of water of crystallization to the atmosphere is termed efflorescence.

Key Concept

Properties, Preparation, and Uses of Major Sodium Compounds
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Topics

Alkali Metals: Sodium Extraction, Properties, and Compounds

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