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Zorluk: ZorChemistry in Daily Life and Industrial Applications

With reference to everyday chemical compounds and their industrial applications, consider the following statements:

1. Bleaching powder (CaOCl2CaOCl_2) acts as a strong oxidizing agent and liberates chlorine gas when reacting with atmospheric carbon dioxide.
2. Baking soda (NaHCO3NaHCO_3) decomposes thermally during cooking to produce oxygen gas, which causes dough to expand and rise.
3. Plaster of Paris (CaSO4⋅12H2OCaSO_4 \cdot \frac{1}{2}H_2O) is manufactured by heating gypsum at 373 K373\text{ K}, and sets into a hard solid mass of gypsum upon addition of water.

Which of the statements given above is/are correct?

  1. A
    1 and 2 only
  2. B
    2 and 3 only
  3. 1 and 3 onlyCevap
  4. D
    1, 2 and 3

Cevap

Statements 1 and 3 only are correct.
The correct response identifies statements 1 and 3 as true while recognizing statement 2 as false. Bleaching powder (CaOCl2CaOCl_2) reacts with atmospheric CO2CO_2 to release chlorine gas, acting as a strong oxidant. Plaster of Paris is produced by controlled heating of gypsum at 373 K373\text{ K} and hardens back into gypsum upon hydration. Baking soda releases carbon dioxide gas upon heating, not oxygen.

Adım Adım Çözüm

1
Analyze Statement 1 regarding bleaching powder (CaOCl2CaOCl_2).
Bleaching powder acts as a bleaching and oxidizing agent in various chemical industries. When exposed to atmospheric carbon dioxide, it reacts according to CaOCl2+CO2→CaCO3+Cl2↑CaOCl_2 + CO_2 \rightarrow CaCO_3 + Cl_2 \uparrow, releasing chlorine gas.
This confirms statement 1 is scientifically accurate.
2
Analyze Statement 2 regarding baking soda (NaHCO3NaHCO_3).
When heated during cooking, sodium hydrogen carbonate undergoes thermal decomposition: 2NaHCO3→ΔNa2CO3+H2O+CO2↑2 NaHCO_3 \xrightarrow{\Delta} Na_2CO_3 + H_2O + CO_2 \uparrow. The evolved gas is carbon dioxide (CO2CO_2), not oxygen (O2O_2).
Carbon dioxide bubbles trap in the dough, causing bread/cakes to rise and become soft and spongy. Therefore, statement 2 is incorrect.
3
Analyze Statement 3 regarding Plaster of Paris (CaSO4⋅12H2OCaSO_4 \cdot \frac{1}{2}H_2O).
Gypsum (CaSO4⋅2H2OCaSO_4 \cdot 2H_2O) loses three-fourths of its crystallization water when heated carefully at 373 K373\text{ K} (100∘C100^\circ\text{C}) to form calcium sulfate hemihydrate (Plaster of Paris). When mixed with water, it rehydrates to form hard crystalline gypsum.
This confirms statement 3 is scientifically accurate.

Anahtar Kavram

Chemical formulas, preparation methods, and everyday reactions of industrial salts (Bleaching powder, Baking soda, and Plaster of Paris).
Tahmini Süre:1m 30s
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Konular

Chemistry in Daily Life and Industrial Applications

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