Na reacts with non-metallic elements

The reaction between Na and H₂O

When Na encounters a salt/alkali solution, it reacts directly with water: 2Na 2H₂O==2NaOH H₂↑

Then consider whether there will be any follow-up reactions

Look at the product

Look at other factors

①2Na 2H₂O==2NaOH H₂↑

②Na reacts with saturated Ca(OH)₂: generates gas and precipitates ↓ H₂O will decrease, causing Ca(OH)₂ to precipitate

②NaOH NH₄Cl==NH₃↑ H₂O NaCl

②3NaOH FeCl₃==Fe(OH)₃↓ 3NaCl

②2NaOH CuSO₄==Na₂SO₄ Cu(OH)₂↓

Na₂O H₂O==2NaOH

Na₂O CO₂==Na₂CO₃

-Disproportionation reaction of 1-valent O

Oxidizing

react with indicator

Destroy organic pigments

Combine organic pigments to produce colorless substances

Adsorb colored substances to cause fading

reaction equation

Some reaction characteristics

CO₃²⁻ is more hydrolyzed

Heat to constant weight

Inject sufficient CO₂ gas

Add appropriate amount of NaOH solution

After heating, it is NaHCO₃ that produces the gas that makes clear lime water turbid.

After heating, the mass decreased is NaHCO₃

Gas method: When lower concentration hydrochloric acid is added dropwise, the bubbles immediately generated are NaHCO₃

pH measurement method: Measure the pH of two solutions of the same concentration. The one with the larger pH is Na₂CO₃

NaCl CO₂ NH₃ H₂O==NaHCO₃↓ NH₄Cl

△ 2NaHCO₃==Na₂CO₃ H₂O CO₂↑

Through NH₃ Through CO₂ △ Saturated brine——→ammonia brine——→NaHCO₃ precipitation——→Na₂CO₃ product (alkaline) | |→CO₂ (recycled) |→NH₄Cl₃、NaCl

Although NaHCO₃ is soluble in water, its solubility is not large. The solution is easily saturated and solids precipitate. In order to make the solution as saturated as possible, in reaction ①, the amounts of NaCl and CO₂ need to be sufficient. Therefore, in the actual operation process, you need to pay attention to the following matters: (1) Use saturated salt water to increase the Na concentration and promote the generation of NaHCO₃ (2) Pass NH₃ first to make the solution weakly alkaline, and then pass CO₂ to increase the solubility of the acidic gas CO₂ in water.