The main component of household alkali is Na2CO3, and what does its substance category belong to

Conjecture 1: The solution is red.

Conjecture 2: Na2CO3 + 2HCl ==2NaCl + H2O + CO2 (gas).

Conjecture 3: Na2CO3 + Ca(OH)2 ==CaCO3(precipitate) +2NaOH

Conjecture 4: A small amount of Na2CO3 solution was placed in the test tube staring calendar, and BaCl2 solution was added dropwise, resulting in a white precipitate.

Leaseback cons are satisfied.

nahso4

Acidic salts. Okay no!

Common strong acids in high school:

h2so4.

hcl.hbr.

Weak acid, strong alkali and OH

The acidity and alkalinity of the weak alkali plus (OH) salt in aqueous solution is mainly determined by the degree of hydrolysis of the ions ionized by the salt.

Take na2co3 as an example.

He dissolves and ionizes two ions.

Sodium and carbonate ions.

Carbonate ions in water will absorb hydrogen ions ionized by water molecules (water can be ionized, ionized to produce hydrogen ions and hydroxide ions.

Because the quantity is equal and the concentration is low, it is neutral. Therefore, the concentration of hydroxide is greater than that of hydrogen ions, so the solution is alkaline.

And why was my nahso4 acidic at the beginning?

Only NaOH is a base.

NaHCO3 (acid salt) and Na2CO3 (normal salt) are salts, and their solutions are alkaline.

Containing h are acid salts (except ammonium salts).

Metallic acids are positive salts.

Basic salt: Cu2(OH)2CO3

Metal oxides are generally basic oxides.

Non-metallic oxides are generally acidic oxides.

The salt produced by strong base + weak acid is the obvious base: Na2CO3

The salts produced by strong acids and weak bases are acidic: FeCl3NH4ClCuSO4 sulfuric acid, nitric acid, and hydrochloric acid are strong acids.

Na is a strong base.

The combination of strong acids and alkalis is a neutral salt, such as the combination of hydrochloric acid and sodium hydroxide, and sodium chloride is a salt, neutral; Sodium hydroxide is a strong alkali, and the salt formed by combining with weak acid is an alkaline salt, such as carbonic acid, sodium carbonate is an alkaline salt.

Na2SO4 is read as sodium sulfur Xuming mountain cha acid, which is a chemical acacia leak composed of metal sodium ions and sulfate ions, which belongs to salt

Therefore, fill in: sodium sulfate; Salt

Question answers: a. Na2CO3 is a compound composed of sodium ions and carbonate ions, which is a salt, so the choice is wrong; Qi clan.

b. The anions generated when Ca(OH)2 is ionized are hydroxide ions, which are alkaline, so the option is correct;

c. CAO is a compound composed of calcium and oxygen-resistant elements, which belongs to oxides, so the choice is wrong;

D. The cations generated by HCL ionization are all hydrogen ions, which are acids, so the wrong option is B

A. NaOH is a compound composed of sodium ions and hydroxide ions, which belongs to peishuo, so option A is in line with the theme of the matching branch. b、na

o is a compound composed of two elements, sodium and oxygen, which are oxides, so option b does not fit the topic; c、na

SO is a compound composed of sodium ions and sulfate ions, which belongs to salts, so option C does not conform to the topic; d、na

CO is a compound composed of sodium ions and carbonate ions, which belongs to salts, so option D does not meet the topic;

So choose A

Option b Commonly known and chemical formula of substance:

Quicklime – CAO

Hydrated lime – Ca(OH)2

Limestone, marble – caco3

Table salt – NaCl

Caustic soda, caustic soda, caustic soda – Naoh

Soda ash, soda - Na2CO3

Baking soda – naHCO3

Rust, hematite – Fe2O3

Hematite – Fe3O4

Diamond, graphite - c

Dry ice – CO2

Ice – H2O

Natural gas (methane) — CH4

Alcohol (ethanol) — C2H5OH

Acetic acid (acetic acid)—CH3COOH

Choose B, A soda ash belongs to salt, C is calcium oxide not limestone, D blue alum or bile alum is copper sulfate pentahydrate instead of pure copper sulfate.

a. Sodium carbonate can ionize sodium ions and acid ions, which belongs to sodium salt, so a is correct;

b. Sodium carbonate can ionize sodium ions and acid ions, but cannot ionize hydroxide ions, which does not belong to alkali, and the alkali is a compound of ionized anions that are all hydroxide ions, so B is wrong;

c. Sodium carbonate can ionize sodium ions and acid ions, and the anion is carbonate ion, which belongs to carbonate, so C is correct;

d. The acid corresponding to sodium carbonate is carbonic acid, which is oxygenated acid, so D is correct and B is selected