20 mL of 0.1 M NH 4 OH is mixed with 40 mL of 0.05 M HCl. The pH of the mixture is nearest to: (Given: K b ( NH 4 OH )=1 × 10-5, log 2=0.30, log 3=0.48, log 5=0.69, log 7=0.84, log 11=1.04 )

Question

20 mL of 0.1 M NH 4 OH is mixed with 40 mL of 0.05 M HCl. The pH of the mixture is nearest to: (Given: K b ( NH 4 OH )=1 × 10-5, log 2=0.30, log 3=0.48, log 5=0.69, log 7=0.84, log 11=1.04 ) (A) 3.2 (B) 4.2 (C) 5.2 (D) 6.2

Tardigrade Admin · Accepted Answer

<img class="img-fluid question-image" alt="image" src="https://cdn.tardigrade.in/img/question/physics/e73a5c23b2ccd98a5fbe8a804446e634-.png" /> pH =( pK w - pK b - log C /2) =(14-5+1.48/2)=5.24

Q. $20 m L$ of $0.1 M N H_{4} O H$ is mixed with $40 m L$ of $0.05 M H Cl$ . The $p H$ of the mixture is nearest to:
(Given: $K_{b} (N H_{4} O H) = 1 \times 1 0^{- 5}, lo g 2 = 0.30$ , $lo g 3 = 0.48, lo g 5 = 0.69, lo g 7 = 0.84$ , $lo g 11 = 1.04$ )

$3.2$

$4.2$

$5.2$

$6.2$

$p H = \frac{p K _{w} - p K _{b} - l o g C}{2}$
$= \frac{14 - 5 + 1.48}{2} = 5.24$

Q. 20mL of 0.1MNH4​OH is mixed with 40mL of 0.05MHCl. The pH of the mixture is nearest to: (Given: Kb​(NH4​OH)=1×10−5,log2=0.30, log3=0.48,log5=0.69,log7=0.84, log11=1.04 )

3.2

4.2

5.2

6.2