The percentage of pyridine ( C _ 5 H _ 5 N) that forms pyridinium ion ( C _ 5 H _ 5 N ^ + H) in a 0 . 10M aqueous pyridine solution ( K _ b for C _ 5 H _ 5 N = 1 .7 × 10 ^ - 9 ) is

Correct answer: B. 0 . 013 % cases & C _ 5 H _ 5 N + H _ 2 O & ⇌ & C _ 5 H _ 5 N ^ ⊕ H & + & OH ^ ⊖ t = 0 & C & & & & t = eq & C(1 - α) & & Cα & & Cα cases ∴ K _ b = C α ^ 2 1 - α C α ^ 2 ∴ α = K _ b C = 1.7 × 10 ^ - 9 0.1 = 1.3 × 1 0 ^ - 4 ∴ %α = 1.3 × 10 ^ - 4 × 100 = 0.013%

NEET 2016

Exam: NEET
Year: 2016
Subject: Chemistry
Chapter: Ionic Equilibrium

NEET 2016 · Chemistry · Ionic Equilibrium

The percentage of pyridine ( C _ 5 H _ 5 N) that forms pyridinium...

The percentage of pyridine

\left({C}_{5}{H}_{5}N\right)

that forms pyridinium ion \left({C}_{5}{H}_{5}{N}^{+}H\right)

in a

0 . 10M

aqueous pyridine solution \left({K}_{b}for{C}_{5}{H}_{5}N = 1 .7 \times {10}^{- 9}\right)

Options

A $0 . 0060 %$
B $0 . 013 %$
C $0 . 77 %$
D $1 . 6 %$

Correct answer

B. $0 . 013 %$

Step-by-step solution

\begin{cases} & {\text{C}}_{5}{\text{H}}_{5}\text{N} + {\text{H}}_{2}\text{O} & ⇌ & {\text{C}}_{5}{\text{H}}_{5}{\text{N}}^{⊕}\text{H} & + & {\text{OH}}^{⊖} \\ \text{t} = 0 & \text{C} & & & & \\ \text{t} = \text{eq} & \text{C}\left(1 - \alpha\right) & & \text{C}\alpha & & \text{C}\alpha\end{cases}

∴ {K}_{b} = \dfrac{C{\alpha}^{2}}{1 - \alpha} \approx C{\alpha}^{2}

∴ \alpha = \sqrt{\dfrac{{K}_{b}}{C}} = \sqrt{\dfrac{1.7 \times {10}^{- 9}}{0.1}}

= \text{1.3} \times 1 {0}^{- 4}

∴ %\alpha = 1.3 \times {10}^{- 4} \times 100 = 0.013%

Practice Ionic Equilibrium on Quantrex Academy →

More from Ionic Equilibrium

What amount of NaOH should be dissolved in a 500 mL solution, so that the p^H of solution… MHT CET Medical 2026 Which of the following buffer solutions is used for precipitation of cations of the III A… MHT CET Medical 2026 The degree of dissociation of weak acid is directly proportional to MHT CET Medical 2026 Which from the following is Lewis base? MHT CET Medical 2026 The solubility of Fe(OH)_3 is x mole per liter. Find its K_ sp . MHT CET Medical 2026 The Basic buffer solution is made with 0.1\ M\ NH_4OH and 0.2\ M\ NH_4Cl . If K_b for the… MHT CET Medical 2026 The hydrogen ion concentration of the ocean is about 2 × 10^ -9 \ M . What is the pOH of… MHT CET Medical 2026 Calculate the dissociation constant of a weak monobasic acid if it is 0.04% dissociated… MHT CET Medical 2026 Full Ionic Equilibrium list All NEET PYQs