Question

How do you distinguish between Strong Acids and Weak Acids?

Answer 1

An Acid is a molecule or compound which can donate ${H^ + }$ ion to another compound. They turn Blue Litmus to red. Based on the tendency/strength to furnish ${H^ + }$ions they can be classified as Strong Acids and Weak Acids. Strong acids are completely furnishable in water whereas Weak acids are partially furnished in water.

Complete answer:
So, the difference Between Strong Acids and weak Acid are as follows:

STRONG ACID	WEAK ACID
1. these are the compounds that completely dissociates into their corresponding ions in an aqueous solution	1. These are the compounds that Partially dissociates into corresponding ions in an aqueous solution
2. They release all hydronium ions in water.	2. They do not release all the hydronium ions in water.
3. Their Ph ranges from 1-2	3. Their Ph ranges from 3-5
4. Examples: $Hcl$ $HN{O_3}$ ${H_2}S{O_4}$	4. Examples:$C{H_3}COOH$ $HN{O_2}$

Let us have a look on the reaction of Strong Acid:
Strong Acids undergo dissociation as shown below:
$HCl \to {H^ + } + C{l^ - } \\\ {H_2}S{O_4} \to 2{H^ + } + S{O_4}{2^ - } \\\$
let us have a look on the reaction of weak Acid:
Weak acid undergoes dissociation as shown below:
$C{H_3}COOH\overset {} \leftrightarrows C{H_3}CO{O^ - } + {H^ + }$

Note: Always remember that in the case of strong acids only first proton or the hydronium ion (${H^ + }$) will be completely dissociated and the corresponding ${H^ + }$ions will be partially dissociated.
For example: in the given reaction
${H_2}S{O_4} \to {H^ + } + HS{O_4}^ - \\\ HS{O_4}^ - \overset {} \leftrightarrows {H^ + } + S{O_4}^{2 - } \\\$
Here only ${H_2}S{O_4}$ will get completely dissociated and hence it is a strong acid. But $HS{O_4}^ -$ will not get completely dissociated and hence it is not a strong acid. It is a common mistake which many people make with Acids.