A chemistry competition question about several acid base theories

protonbases; solvent bases;

Lewis acid. First, in the HF system, one proton can be accepted to generate HF, and Hannan gives proton, so it is a proton base according to the proton theory.

The second is the solvent self-coupling ionization, which can ionize (BRF2)+ as an acid and ionized as a base (BRF4)-. It is obviously a solvent base.

The third, which accepts electrons, is therefore Lewis acid.

Goo (b Wrong) Originally, my consideration was illustrated from the perspective that both of them are tetrahedral structures and have high stability. In fact, both PF6- and PF4+ are definitely present. Of course, the same result may be obtained from the angle that the positive hexahedron has a higher degree of pf6-negative charge dispersion, resulting in increased anion stability.

However, I personally feel that it is inappropriate to use soft and hard acids and bases to explain, and this theory mainly deals with the interaction between positive and negative ions of ionic compounds. I'm sorry for the mistake, ......

1、cao+h2o=ca(oh)2

Quicklime is calcium oxide, and calcium oxide reacts with water to form calcium hydroxide, which is equivalent to absorbing water. The lumpy form is a calcium hydroxide (hydrated lime) solid.

2. There is actually sulfuric acid

Set: x tons of iron required.

fe+h2so4=feso4+h2↑

x152/x=98/

x = tons. Answer: Tons of ferrous sulfate are obtained.

The main component of rust is Fe2O3, in order to remove the rust on the nails, it can be put into excess hydrochloric acid, and the rust is observed to dissolve, and the solution gradually turns brownish-yellow from colorless, and then turns to light green, and the chemical equation of the reaction between rust and hydrochloric acid Fe2O3 + 6HCl = 2FeCl3 + 3H2O is written. After a while, bubbles were observed to be emitted because (expressed by the chemical equation) Fe +2HCl = FeCl2 + H2.

Fe2O3·XH2O gradually dissolves red, yellow Fe2O3+6HCl=FeCl3+3H2O, and colorless gas is generated.

fe+2hcl=fecl2+h2

1、fe2o3

2. Fade away.

3. Colorless. 4. Yellow.

5. Fe2O3+6HCl=2FeCl3+3H2O6, air bubbles are generated on the nails.

7、fe+2hcl=fecl2+h2↑

Fe2O3, gradually dissolved, colorless, brownish-yellow, Fe2O3+6HCl=2FeCl2+3H2O, the solution changes to brownish-yellow again, O2+4FeCl2+2H2O=2FeCl3+2Fe(OH)2Cl

Solution: CO2 + Ca(OH)2 = CaCO3 precipitation + H2OM (CO2) 10g

m(co2)=

Na2CO3 + 2HCl = 2NaCl + H2O + CO2 gas.

m(na2co3)

m(na2co3)=

So the mass fraction of sodium carbonate in the sample is 100%=53%.

At room temperature, the pH of dilute sulfuric acid of 10 (less than).

2 pH of dilute sulfuric acid only. If you want to increase the pH value of dilute sulfuric acid, there are methods to be taken.

1. There is no chemical reaction: add water.

2. There are chemical reactions that occur: sodium hydroxide, sodium carbonate.

A: NaOH, BACl2, NaCl

B: FeCl3, CuSO4,

Precipitation: iron hydroxide, barium sulfate, copper hydroxide 3 kinds.

NACL is also present

First of all, A is colorless, so it does not contain CuSO4 (blue) and FeCl3 (yellow), so it contains BaCl2 and NaCl (plus the following, you said that there are five substances, I don't know which one there is, so I made it according to four).

The resulting pellet has baso4

Eventually, CuCl2 FeCl3 NaCl is also present

Because the water division of workshop A is colorless, it does not contain cuso4, and there are the remaining three. .The questions are all wrong.,Why are there only four substances?。。。 Hurry up and change it.

1) Calcium hydroxide solution.

2) Carbon dioxide + calcium hydroxide to generate calcium carbonate precipitate + water, (it is inconvenient to write the equation here, please add it yourself).

The objective was to confirm the reaction of carbon oxide with calcium hydroxide.

3) Carbon dioxide hail + 2 sodium hydroxide to generate calcium carbonate precipitation + water.