Question

Which one of the following is not a strong electrolyte?
A.$HCl$
B.$HN{O_3}$
C.${H_2}S{O_4}$
D.$HCOOH$

Answer 1

We need to know that the electrolyte is a gel or liquid which consists of ions that can be decomposed by using electrolysis. Which means, it is a substance which dissociates and there is a formation of ions in solution and it obtains the ability to conduct the electricity. Calcium, potassium, sodium, phosphate and chloride are some examples of electrolytes.

Complete answer:
We have to remember that the hydrochloric acid is a chemical element having the symbol, HCl. And it is an example of a strong electrolyte. Because, when it is dissolved in water, there is a formation of ${H^ + }$ and $C{l^ - }$ ions. Hence, option (A) is incorrect.
Nitric acid is a chemical element having the symbol $HN{O_3}$. And it is an example of a strong electrolyte. Hence, option (B) is incorrect.
The sulphuric acid is a chemical element having the symbol ${H_2}S{O_4}$. And it is an example of a strong electrolyte. Hence, option (C) is incorrect.
Formic acid is a chemical element having the formula $HCOOH$ and it is also known as methanoic acid. Among the given options, formic acid is not an example of strong electrolyte and it is a weak electrolyte and it is a weak carboxylic acid. Because, here only little amount of the dissolved solute is occurring in the form of ions. When it is dissolved in water, all hydrogen present in the formic acid will not release into the solution. Therefore, the formic acid is a weak electrolyte.

Hence, option (D) is correct.

Note:
We have to remember that the electrolyte is the compound which dissociates into anions and cations when it is dissolved in water. The anion is the negative charged ions and the cation contains the positive charged ions. According to the strong electrolytes, when it is dissolved in water, it completely ionizes into ions. But in the case of weak electrolyte, it will only partially ionize.