Salt Preparation And Qualitative Analysis (Zhengkang Jinan)

When an insoluble compound is reacted to prepare an insoluble salt, a coating would be formed around the compound, preventing further reaction. This coating acts as a barrier, preventing any additional reactions from occurring. Therefore, the correct answer is "coating".

Heating a solution to saturation allows for the maximum amount of solute to dissolve in the solvent. Cooling the solution causes the solute to come out of solution and form crystals, which can then be separated from the remaining liquid through filtration. This process is known as crystallisation.

A salt that is an oxide/hydroxide is called a base because bases are substances that can accept protons or donate hydroxide ions in a chemical reaction. Oxides and hydroxides are examples of bases as they can react with acids to form salts and water. Therefore, a salt that is an oxide/hydroxide would fall under the category of a base.

When an insoluble base reacts with an acid, it forms a salt and water. In this reaction, the base and acid combine to produce a salt, which is a compound formed when the hydrogen ion from the acid is replaced by a metal ion from the base. Additionally, water is also produced as a byproduct of the reaction. Therefore, the correct answer is "Salt and water."

When two soluble reactants are added together, they undergo a chemical reaction that forms a solution with a precipitate. A precipitate is a solid that forms from the reaction of two soluble substances. In this case, the reactants are both soluble, meaning that they dissolve easily in water. However, when they are mixed together, a chemical reaction occurs and a solid precipitate is formed, indicating that the reaction has taken place.

Copper hydroxide is not soluble because it is an insoluble compound. Insoluble compounds do not dissolve in water and instead form a precipitate. Copper hydroxide is a blue solid that forms when a solution containing copper ions reacts with a base.

Precipitation is not a method of preparing soluble salts because it involves the formation of insoluble salts. In precipitation, two soluble salts react together to form an insoluble salt, which then precipitates out of the solution. The other methods mentioned, such as metal-acid reaction, carbonate-acid reaction, and titration, all involve the formation of soluble salts through various chemical reactions.

The correct answer is Silver+Nitric acid. This can be inferred from the information given in the question, which states that the metal-acid reaction shown in the video involves Silver and Nitric acid.

Sodium hydroxide is not prepared by titration because titration is a technique used to determine the concentration of a solution by reacting it with a solution of known concentration. Sodium hydroxide is typically prepared by the electrolysis of sodium chloride or by the reaction of sodium with water.

Sodium chloride is not prepared by crystallization because it is a highly soluble salt that is commonly found in nature as a mineral called halite or rock salt. It is obtained through mining or by evaporating seawater. Crystallization is a process used to purify and obtain solid crystals of a substance from a liquid solution, but in the case of sodium chloride, it is not necessary as it is already available in a pure form.