Reaction of Chlorine and Sodium Hydroxide*
Summary of Key Points
Original 2020-11-12 15:00 Centennial Spirit
1. Properties of sodium and its compounds
1. Reaction of sodium with air
①Sodium is slow in air Oxidation: 4Na+O2==2Na2O ②Sodium burns in air: 2Na+O2△(====)Na2O 2.
One mole of sodium metal reacts fully with oxygen, and one mole of electrons is transferred.
2. Sodium reacts with water
Na+2H2O = 2NaOH+H2 ↑(The reactant coefficient is 2)
Phenomenon: ①Sodium floats on the water surface ; (2) Melted into silvery white particles; ③Swimming up and down the water surface; (4) Accompanied by whistling sound; (Floating Fragrance Red)
The reaction between sodium and acid: first acid and then water.
Reaction with sodium: with water
Reaction between sodium and salt: first water and then salt.
Any solution has gas, saturated or insoluble has precipitation.
Sodium peroxide Na2O2
Oxide
Na2O
Na2O2
Oxygen valence
――2
――1
Building Conditions
Normal Temperature
Hot
Color, State
White solid
Light yellow powder
Reaction to H2O
Na2O+H2O=2NaOH
2Na2O2+ 2H2O=4NaOH+O2↑
Reaction with CO2
Na2O+CO2= Na2CO3
2na 2 o 2+2co 2 = 2na 2 co 3+O2 ↓
Reaction with acid
Na2O+2HCl=2NaCl+ H2O
2Na2O2+4HCl=4NaCl+2H2O+O2↑
Heat Stability
Unstable and easily oxidized to Na2O2.
Relatively stable
Bleaching
No
Yes
1. Sodium peroxide reacts with water: 2Na2O2+2H2O=4NaOH+O2↑ (the reactant coefficient is 2)
2. The reaction of sodium peroxide and carbon dioxide: 2Na2O2+2CO2=2Na2CO3+O2 (the reactant coefficient is 2)
Xg hydrogen gas mixed with carbon monoxide gas,After complete combustion, add sodium peroxide to increase Xg weight.
Sodium carbonate and sodium bicarbonate NaHCO3 and Na2CO3
Comparison of sodium carbonate and sodium bicarbonate
Soda
Sodium bicarbonate
Popular names
Or soda ash.
Sodium Bicarbonate
Color State
White Crystals
Fine White Crystals
Water Soluble
Soluble in water, alkaline solution makes phenolphthalein red.
Soluble in water (but not as soluble as Na2CO3), the solution is alkaline (phenolphthalein turns light red).
Thermal stability
Stable, not easy to decompose when heated.
Easily decomposed by heat
2NaHCO3 == Na2CO3+CO2↑+H2O
Reaction with acid
CO32- + H+= HCO3-
HCO3-+ H+ = CO2↑+H2O
Under the same conditions, the CO2 release rate of sodium bicarbonate is faster than that of sodium carbonate.
Reaction with base
na2co 3+Ca(OH)2 = CaCO3+2 NaOH Co32-Metathesis reaction with metal cation
Sodium bicarbonate + hydrogen Sodium Oxide = Sodium Carbonate + H2O
HCO3- +OH-= H2O+CO32-
With H2O and Carbon Dioxide
Sodium Carbonate + Carbon Dioxide + H2O = Carbonic Acid Sodium hydrogen
CO32-+H2O+CO2 =H CO3-
No reaction
1. Add dilute hydrochloric acid: na2co 3 +HCl = NaCl+nah co 3+HCl = NaCl+H2O+CO2 ↑ (bubbles will appear later)
Add dilute hydrochloric acid to sodium bicarbonate: NaHCO3+ HCl = NaCl+H2O+CO2↑ (will A large amount of gas will be generated quickly)
Add sodium carbonate solution to hydrochloric acid: Na2CO3+ 2HCl = 2NaCl+H2O+CO2↑ (slowly generate a large amount of gas)
2. Add sodium carbonate solution Carbon dioxide is introduced into the medium: Na2CO3+CO2+H2O=2NaHCO3
3. Sodium bicarbonate is thermally decomposed: 2nachco3△ (= = = =) Na2CO3+H2O+CO2 ↑.
4. The reaction of sodium hydroxide and sodium bicarbonate: NaOH+NaHCO3=Na2CO3+H2O
The substance that distinguishes sodium carbonate and sodium bicarbonate can be acid or salt, but not It is alkali.
Two. Properties of Chlorine and Its Compounds
1. Comparison of liquid chlorine, fresh chlorine water and long-term chlorine water (Illumination) 2HCl+O Youyou Resource Network 2 ↑Among them, HCLO hypochlorous acid has strong oxidizing and drifting properties, and plays the role of disinfection and bleaching. Hypochlorous acid is weakly acidic, unstable, decomposes when exposed to light or heat, and will become invalid if left for a long time.
(2) Prepare bleaching powder liquid, bleaching powder and bleaching powder concentrate
Bleaching solution: Cl2+2NaOH = NaCl+NaClO+H2O. Its active ingredient NaClO is much more stable than HClO and can be stored for a long time.
*** Bleach powder (available chlorine 35%) and bleach powder concentrate (fully reacted available chlorine 70%): 2cl 2+2ca(oh)2 = CaCl 2+ca(clo)2+2h2o
3, the nature of chlorine
Na+Cl2 ignition (= = = = =) 2Na+Cl2 (white smoke) H2+Cl2 ignition (== ===) 2HCl (white mist) phosphorus burns in chlorine (white smoke)
4. Reaction of chlorine and sodium hydroxide Cl2+2NaOH=NaCl+NaClO+H2O (chlorine tail gas treatment)
5. Bleaching powder (chlorine can be introduced into lime slurry) 2cl 2+2ca(OH)2=CaCl 2+Ca(ClO)2+2H2O CaCl 2 and Ca(ClO)2 are called bleaching powder.
Bleaching powder deteriorates in air: Ca(ClO)2+CO2+H2O=CaCO3↓+2HClO
Third, the amount of substance is The physical quantity relationship of the center
1. Physical quantity-the unit of substance-mole (mol)
①n= N/NA N represents the number of particles NA Gadereau constant NA≈6.021023 mol-1
2. The molar mass of the substance m
②n= m/M
m represents the mass of the substance. m is the molar mass, which is numerically equal to the relative atomic mass or molecular mass of the substance. The unit is GMOL One.
3. The molar volume of the gas Vm
③n=V/Vm V is the volume of the gas in liters (L) Vm is the molar volume of the gas. Under standard conditions, 1 mole of gas is 22.4 liters.
When the temperature and pressure are constant, Vm is a constant value, and the unit of Vm is L mol-1. Avogadro’s Law: At the same temperature and pressure, any gas of the same volume contains the same number of molecules. Therefore, it is also called the law of four sameness, also called the law of five sameness (five sameness refers to the same temperature, same pressure, same volume,same number of molecules, same number of substances).
Corollary: Law
(1) At the same temperature and pressure, V1/V2=n1/n2
(2) At the same temperature and pressure Under the volume, p1/p2=n1/n2=N1/N2
(3) When the mass is equal to the same temperature and pressure, V1/V2=M2/M1
4. The number concentration of the solute in the solution C
④n=cV C is the concentration of the solute in the solution, the unit is mol·L-1v, the volume of the solution, the unit is L (L)
5. Preparation and error analysis of a concentrated solution of a certain substance
(1) The volumetric flask is used to prepare a concentrated solution of a certain amount of substance.