Question

Which of the following is acidic in nature?
A. Lime juice
B. Human blood
C. Lime water
D. Antacid

Answer 1

Hint: We know that the acidic strength of compounds is considered by its ability to donate protons in the solution. The chemical species whose pH value lies between \[0 - 7\] is considered as acidic in nature. Generally acidic compounds possess sour taste. In early days acid was defined as a substance which tastes sour, reacts with metal and turns blue litmus to red.

Complete step by step answer:
> So we can identify the given substance with the help of litmus paper whether they are acidic in nature or not. Lime juice is acidic in nature because it possesses citric acid and it has pH value approximately $2 - 3$ which means it is highly acidic in nature. Human blood is alkaline in nature because of the presence of bicarbonate. it has pH value $7.45$ . Lime water can be prepared by mixing calcium hydroxide with water and it has a pH value $12.4$ so this is basic or alkaline in nature.
> Antacids are used to neutralize the excessive effect of acid on our stomach . They are able to neutralize stomach acid because of their basic nature. Hence antacids are also alkaline in nature .
So only lime juice is acidic in nature among the given options.

So, the correct answer is “Option A”.

Note:
1- Acids in aqueous solution conduct electricity.
2- It reacts with bases and forms salt and water.
3- The reaction of acid-base is known as neutralization reaction.
4- Acid turns blue litmus paper to red litmus paper hence litmus paper is used as an indicator.
5- Acids react with active metals and produce hydrogen gas.