Question

The pH of 1 N aqueous solutions of HCl, CH$_3$COOH and HCOOH follows the order:

• A. HCl $>$ HCOOH $>$ CH$_3$COOH
• B. HCl $=$ HCOOH $>$ CH$_3$COOH
• C. CH$_3$COOH $>$ HCOOH $>$ HCl
• D. CH$_3$COOH $=$ HCOOH $>$ HCl

Hint:

The stronger the acid, the lower its pH value. Therefore, the pH order is the reverse of the acid strength order.

Answer 1

The Correct Option is C

Step 1: {Understanding the Strength of Acids} 
Stronger the acid, lower is the pH, and weaker the acid, higher the pH. 
Step 2: {Order of Acid Strength} 
The strength of the given acids is in the order: \[ {HCl}>{HCOOH}>{CH}_3{COOH} \] 
Step 3: {Order of pH} 
Hence, their pH is in the order: \[ {CH}_3{COOH}>{HCOOH}>{HCl} \] Thus, the correct answer is (C).