JEE CHEMISTRY MCQ: Equilibrium

1 Hard

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Application +4 | -1

The ionisation constant of an acid,

K_a

is the measure of strength of an acid. The

K_a

values of acetic acid, hypochlorous acid and formic acid are

1.74 \times 10^{-5}

3.0 \times 10^{-8}

and

1.8 \times 10^{-4}

respectively. Which of the following order of

\mathrm{pH}

0.1 \mathrm{~mol}\,\mathrm{dm}^{-3}

solutions of these acids is correct?

View answer and explanation

Correct option: B

Hypochlorous acid

>

acetic acid

>

formic acid

Option B (Hypochlorous acid

>

acetic acid

>

formic acid) is correct because pH increases with decreasing Ka value, indicating weaker acidity.

More Questions from Equilibrium

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\mathrm{K}_1

\mathrm{K}_2

\mathrm{N}_2(\mathrm{~g})+\mathrm{O}_2(\mathrm{~g}) \rightleftharpoons 2 \mathrm{NO}(\mathrm{g})\quad\ldots

\mathrm{NO}(\mathrm{g}) \rightleftharpoons \frac{1}{2} \mathrm{~N}_2(\mathrm{~g})+\frac{1}{2} \mathrm{O}_2(\mathrm{~g})\quad\ldots

K{a_1},\,\,\,K{a_2}\,\,\,\mathrm{and}\,\,\,K{a_3}

\begin{array}{l} {H_2}S\leftrightharpoons{H^ + } + H{S^ - }\\ H{S^ - }\leftrightharpoons{H^ + } + {S^{2 - }}\\ {H_2}S\leftrightharpoons2{H^ + } + {S^{2 - }} \end{array}

K{a_1},\,\,K{a_2}\,,K{a_3}

\mathrm{pH}

0.1 \mathrm{~M}-\mathrm{N}_2 \mathrm{H}_4

\mathrm{N}_2 \mathrm{H}_4,

K_{{b}_1}=3.6 \times 10^{-6}, K_{{b}_2}=6.4 \times 10^{-12}, \log 2=0.3

\log 3=0.48

{\text{Ba}}{{\text{O}}_2}(s) \rightleftharpoons {\text{BaO}}(s) + {{\text{O}}_2}(g);\Delta H = - {\text{ve}}.

\text{O}_2