★ Solution :-

Yes, it is indeed a true report that the pH of lemon juice is 2.2 . In order to understand the solution of this question. We must look for the answer of this question using various aspects.

Let's firstly understand what is pH .

• According to 10th grade level, pH simply means Hydrogen ion concentration (H⁺) in a solution. As we know that H⁺ ion is very less stable we can refer the pH as the concentration of H₃O⁺ (Hydronium) ion concentration.

The lesser the pH more is the acidic character and the more the pH more is the basic character.

This was a brief introduction to the word pH.

Now let's come back to our question.

Here it is asserted that a solution with pH as 2.2 is very much corrosive in nature. And since lemon juice has that ph then why doesn't it causes harm to us ?

There are several reasons for it.

◍ In our stomach : We all might have witnessed a situation that Lemon Juice is said to be good for digestion. This is because it enhances the process of digestion in our stomach due to its acidic nature. In our stomach there is a lining of mucus on its walls. This lining is so rigid and tough that it doesn't gets corroded easily by the action of acids. This layer protects the walls of stomach from getting corroeded by acids. And when this acids passes through small intestine it is treated with Bile Juice which is basic in nature. This neutralises the acidic nature by neutralization reaction and thus our body doesn't gets any harm from this acid.

◍ On our skin : We see that lemon is used as a cosmetic or home remedy to treat pimples on the face. Pimples arise due to more layer of fats which get acted by sweat and heat under our skin. And we know that most fats are basic in nature. When lemon is applied on skins, this base of fat neutralises the lemon juice and thus makes it a neutral solution which isn't corrosive.

◍ General Fact : It is usually seen that whenever an acid in our body is present either there is a protective layer or any base in our body is present to neutralize it. It's the functioning of the body itself.

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★ More to know :-

• What does acidic character mean ?

Acidic Character simply means that when a solvent is dissolved in water, then the solvent should release Hydrogen or Hydronium ion in that aqueous solution. The rate of dissociation of this ion decides it's acidic strength. Acids have pH less than 7 . Lesser is the pH value, more is the acidic character. Acids always show their ph colours in aqueous in presence of moisture.

• What does basic character mean ?

Basic Character simply means that when a solvent is dissolved in water, then that solvent should release Hydroxide ion (OH¯) ion in that aqueous solution. The rate of dissociation of Hydroxide ion decides the basic strength of a solution. More is the pH value, more is the basic character. Bases have pH more than 7. Bases show their character in aqueous solutions called as Alkalis.

• Fact to know !!

Our stomach has concentrated HCl (Hydrochloric Acid) which makes the digestion of food possible. As shown in the attachment of qúestions, the part mentioned as gastric juices represents the HCl present in stomach and its pH value. The lining of mucus even protects our stomach from getting damaged due to the action of HCl.

Verified answer

Well, the pH value of lemon is 2.2 and it doesn't harm the body because of specific reason. You shouldn't just squeeze the lemon and drink it right away as it is harmful for the upper layer of our tooth. But once it starts digesting, it will alkalise and will be good for health.

Hope you got the answer. If this answer didn't satisfy you, then you can ask for explanation from a moderator :)