Ionic EquilibriumHard
Question
The dissociation constant of formic acid is 0.00024. The hydrogen ion concentration in 0.002 M-HCOOH solution is nearly
Options
A.6.93 × 10−4 M
B.4.8 × 10−7 M
C.5.8 × 10−4 M
D.1.4 × 10−4 M
Solution
$\alpha = \sqrt{\frac{K_{a}}{C}} = \sqrt{\frac{0.00024}{0.002}} = 0.346\text{ or 34.6\%}$
Hence, α cannot be neglected.
$K_{a} = \frac{\alpha^{2}.C}{1 - \alpha} \Rightarrow 0.00024 = \frac{\alpha^{2} \times 0.002}{1 - \alpha} \Rightarrow \alpha = 0.29 $$$\text{Now, }\left\lbrack H^{+} \right\rbrack = C\alpha = 0.002 \times 0.29 = 5.8 \times 10^{- 4}$$
Create a free account to view solution
View Solution FreeMore Ionic Equilibrium Questions
From separate solutions of for sodium salts NaW, NaX, NaY and NaZ has pH 7.0, 9.0 10.0 and 11.0 respectively. When each ...An acid base indicator which is a weak acid has a pKa value = 5.5. At what concentration ratio of sodium acetate to acet...When 20 mL of M/20 NaOH is added to 10 mL of M/10 HCl, the resulting solution will...Which of the following mixture gives a buffer solution with $pH = 9.25$ ?Given : ${pK}_{b}\left( {NH}_{4}OH \right) = 4....The species present in solution when CO2 is dissolved in water are...