1, sulfuric acid solution, NaCl solution, etc. , the density is greater than 1, and the greater the concentration, the greater the density.

2. Alcohol solution, ammonia water, etc. , the density is less than 1, the greater the concentration, the smaller the density.

The conclusion that this article on the Internet wants to prove is:

The higher the concentration of (1), the higher its density, and it is mixed with aqueous solutions of different solute concentrations with the same volume (ρ >); 1), the mass fraction of solute in the mixed solution is greater than the average mass fraction of solute in the two solutions before mixing.

(2) When the concentration is high, its density is low, and it is mixed with equal volume of aqueous solutions with different solute concentrations (ρ

These two conclusions are often examined in the college entrance examination, and the corresponding substances are the four you mentioned.

As for your question, simply understand that the density of concentrated sulfuric acid is 1.84g/cm3, which is greater than 1, so the density of sulfuric acid solution is between 1- 1.84.

It's like mixing hot water and cold water to make warm water.

This is true for salt solutions such as NaCl.

The density of pure ethanol is less than 1, and the density of alcohol solution is also less than 1. The higher the concentration, the closer it is to pure ethanol, and the lower the density.

The same is true of ammonia, whose density is less than 1.