The pH of a solution obtained by mixing of 100 mL of a HCl solution of pH = 2 with 400 mL of another HCl solution of pH = 3 will be

Question

The pH of a solution obtained by mixing of 100 mL of a HCl solution of pH = 2 with 400 mL of another HCl solution of pH = 3 will be (A) 2 (B) 3 (C) 2.5 (D) 2.8

Tardigrade Admin · Accepted Answer

100 mL of a HCl solution of p H=2 ⇒ [H+]=10-2 400 mL of a HCl solution of pH=3 ⇒ [H+]=10-3 Resulting [H+]=(100 × 10-2+400 × 10-3/500) =(1+0.4/500) =(1.4/500)=0.0028 ∵ p H=- log [H+] ∴ p H=- log (0.0028) =2.5

Q. The pH of a solution obtained by mixing of 100mL of a HCl solution of pH=2 with 400mL of another HCl solution of pH=3 will be

2

3

2.5

2.8

100mL of a HCl solution of pH=2 ⇒[H+]=10−2400mL of a HCl solution of pH=3 ⇒[H+]=10−3 Resulting [H+]=500100×10−2+400×10−3​ =5001+0.4​ =5001.4​=0.0028 ∵pH=−log[H+] ∴pH=−log(0.0028) =2.5

Q. The $p H$ of a solution obtained by mixing of $100 m L$ of a $H Cl$ solution of $p H = 2$ with $400 m L$ of another $H Cl$ solution of $p H = 3$ will be