The Factors Determining Acidic Strength

What is an acid?

An acid is a chemical substance that tastes sour when dissolved in water. Acid changes blue litmus paper to red, reacts with metals to give hydrogen, reacts with bases to make salts, and also acts as a catalyst in various reactions to fasten the process.

Some examples of acids and sulphuric acid, nitric acid, hydrochloric acid, and phosphoric acids. There are some organic acids, too, like carboxylic acid, sulfonic acid, and phenol groups.

What is Acid Strength?

Acid strength is defined as the measure of the ability of the acid to lose its H+ ion.

Strong and Weak Acids

• Acids are classified as strong and weak based on how they ionize a solution. A weak acid completely ionizes the solution, whereas a weak one partially ionises.
• Strong acids are more harmful when not handled carelessly, as they cause severe burns where when they come in contact with skin, strong acids are considered more corrosive than weak acids.

• Weak acids are mainly corrosive and are considered essential as they are present in our food and body too.
• Some examples of solid acid are Hydrochloric acid and sulphuric acid.

• A few examples of weak acids are Ethanoic acid, citric acid (found in citric fruits) and acetic acid (found in vinegar).

Factors Determining Acid Strength

You already know that different acids have different acidic strengths and acids with a greater degree of dissociation than a strong acid.

The factors on which strength of an acid(HA) depends the degree of dissociation of an acid depends on two main factors which are:

• Strength of H-A bond
• The polarity of H-A bond

Acid is considered vital the strength of a bond is weaker similarly; if the polarity of HA  bond is greater, the acid is considered vital both of these factors make the dissociation of acid molecules in H+ and A- much more accessible and hence volunteers in increasing the acidity.

Order of Acid Strength 

Order of acidic strength is considered when the H-A bond is between the elements of the same group from the modern periodic table. The strength of the H-A bond depends on element A. On moving downwards in a group, the size increases; hence the polarity decreases. This decrease in the polarity results in increasing acidic strength of the ha bond; for example, the strength of the hydride in group 17 elements increases in order.

HF < HCl < HBr < HI

Factors Affecting Acid Strength of the Acid

• The strength of the H-A bond defines the acidic strength. Weaker bonds are easy to break, which means that less energy is required to break them hence formed with weak strength are stronger acids.

• The polarity of H-A bond is another factor that affects the acidic strength. The higher polarity of a bond makes it easier to break. Hence it makes it a strong acid.
• However, bond strength is more important when we consider and compare acid strengths of elements in the same group of the periodic table, using the above two factors.
• Bond strength is a significant factor to consider when comparing the acidic strength of elements from the same group in the modern periodic table.
• Priority is given to the polarity of the H-A bond when we consider elements that are formed by the elements of the same group in the modern periodic table.
• Atomic size is another factor which affects the acidic strength. However, the size of the hydrogen atom is the same as the size to be considered as of the A. When we move down the group in a modern periodic table the size of the element increases. Hence, the bigger the size of A the stronger the acid.

Conclusion

Acids are the chemical substance which tastes or, when dissolved in water, turns litmus blue litmus paper to read and form salts when it reacts with base and produces H+. In the above article, we learn about acids, acidic strength, and factors that determine the acidic strength of an acid. Read the above article carefully to understand the topic better. Hope this article helped you.