Question

Which of the following solution will have pH close to 1.0 ?

• A. 100 ml of M/10 HCl + 100 ml of M/10 NaOH
• B. 55 ml of M/10 HCl + 45 ml of M/10 NaOH
• C. 10 ml of M/10 HCl + 90 ml of M/10 NaOH
• D. 75 ml of M/5 HCl + 25 ml of M/5 NaOH.

Answer 1

Answer: (D)

75 ml of M/5 HCl + 25 ml of M/5 NaOH.

Answer 2

(1) HCI NaOH

No. of mili eq. = $\frac { 1 } { 10 }$ × 100 = 10

So solution is Neutral

(2)$\frac { 1 } { 10 }$ × 55 = 5.5 $\frac { 1 } { 10 }$× 45 = 4.5

[H+] =$\frac { 1 } { 100 }$ = 10–2 M, pH = 2

(3)$\frac { 1 } { 10 }$ × 10 = 1$\frac { 1 } { 10 }$ × 90 = 9 Basic

(4) $\frac { 1 } { 5 }$× 75 = 15 $\frac { 1 } { 5 }$× 25 = 5

[H+] = 0.1M, pH = 1