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

Question

Which of the following solutions 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

Tardigrade Admin · Accepted Answer

75 mL ( M/ 5 ) HCl = 15 mmol HCl 25 mL ( M/ 5 ) NaOH = 5 mmol NaOH After neutralisation, 10 mmol HCl will be remaining in 100 mL of solution. Molarity of HCl in the final solution = ( 10 / 100 ) = 0.10 pH = - log [H+ ] = - log (0.10) = 1.

Q. Which of the following solutions will have pH close to $1.0$ ?

$100 m L$ of $(M /10) H Cl + 100 m L$ of $(M /10) N a O H$

$55 m L$ of $(M /10) H Cl + 45 m L$ of $(M /10) N a O H$

$10 m L$ of $(M /10) H Cl + 90 m L$ of $(M /10) N a O H$

$75 m L$ of $(M /5) H Cl + 25 m L$ of $(M /5) N a O H$

$75 m L \frac{M}{5} H Cl = 15 mm o l H Cl$
$25 m L \frac{M}{5} N a O H = 5 mm o l N a O H$
After neutralisation, $10 mm o l H Cl$ will be remaining in $100 m L$ of solution.
Molarity of $H Cl$ in the final solution
$= \frac{10}{100} = 0.10$
$p H = - l o g [H^{+}]$
$= - lo g (0.10) = 1.$

Q. Which of the following solutions will have pH close to 1.0 ?

100mL of (M/10)HCl+100mL of (M/10)NaOH

55mL of (M/10)HCl+45mL of (M/10)NaOH

10mL of (M/10)HCl+90mL of (M/10)NaOH

75mL of (M/5)HCl+25mL of (M/5)NaOH