Dilute Acids: Overview, Questions, Preparation

Acids contain hydrogen capable of passing on the protons to other substances and capable of forming a bond with the electrons. When dissolving in water, acids form hydrogen ions (H+). The pH level of acids is less than 7.

Diluted acids are acids that contain a lot of water. The proportion of water is more in these acids as compared to concentrated acids. As the name suggests, these are highly dilute in nature and contain a lot of water. Any type of concentration can be diluted in these acids.

The properties of dilute acids are as follows:

1. Aqueous Solution – The tendency of absorbing the ions depicts the strength of an acid. If the acid to be diluted completely ionizes once diluted, it usually means a strong acid. On the contrary, when the acids are weak, they don't completely dissolve, and the ionisation process is much lower. In the case of weak acids, a lot of molecules remain unionized. 
2. Taste – Acids have a very sour taste. 
3. pH – PH level is the standard benchmark of observing the acidity of an acid. If acid is rubbed on a PH paper strip, the color of the PH paper changes, the color of the PH paper after coming in contact with the acid determines the acid’s acidity level/PH level. 

1. The reaction of acids and metals – When acids react with metals, hydrogen gas is produced. 

For example: Take small flakes of zinc in one test tube and magnesium in another. Pour HCl in the first test tube and sulphuric acid into the second test tube. The reaction takes place, and the gas is released. The validity of hydrogen gas can be tested by bringing the burner near the test tube. The gas will make a pop sound once it is done. The chemical reaction is as follows:

Zn + 2HCl → ZnCl₂ + H₂

Mg + H₂SO₄ → MgSO₃ + H₂

2. The reaction of acids and base – when acids and bases react together, they form salt and water.

For example: In the below reaction, the acid and alkali (hydroxide) react together to form salt and water.

HCl + ZnO → ZnCl₂ + H₂O

3. The reaction of acids and other metals – the acids react with various metals, and all have different chemical formulas and solutions. The rate of reaction depends upon several factors, which are as follows:

• Concentration – the reaction will be slow if the acid is too dilute.
• Temperature – cold solutions attack metals slower than hot solutions
• Surface area – powdered solutions react faster

This parent chapter of Acids, bases, and salts has this nested topic of Diluted Acids. The inclusive weightage overall comes around to 4-5 marks as per the latest structure.

1. How do you explain the reasoning behind concentrated acids being stronger?

Answer: Concentrated acids have less water in them, making the concentration more acidic hence stronger.

2. Explain one indicator property of dilute acids.

Answer: The change in color to blue litmus red.

3. What will happen when Zinc and sodium hydroxide solution react with each other?

Answer: The reaction of zinc of sodium hydroxide is as follows:

2NaOH(aq) + Zn(s) → Na2ZnO2 (s) + H2 (g) (Sodium zincate)

Q: What is the difference between concentrated and dilute acid?

Q: Are dilute acids more dangerous than concentrated acids?

Q: What is the chemical formula of diluted sulphuric acid?

Q: How to dilute a concentrated acid?

Q: What is the chemical formula of dilute ethanoic acid?