Test Index

JEE Advanced 2018 Paper 2

Section: Chemistry

Question : 36 of 54

Marks: +1, -0

[\mathrm{H}^{+}]

(\alpha)

(\mathrm{H}^{+})

\mathrm{H}^{+}

List - I	List - II
P. (10 mL of 0.1 M NaOH+20mL of 0.1 M acetic acid) diluted to 60ML	1. the value of $[\mathrm{H}^{+}]$ does not change on dilution
Q. (20mL of 0.1 M NaOH+20mL of 0.1 M acetic acid) diluted to 80mL	2. the value of $[\mathrm{H}^{+}]$ changes to half of its initial value on dilution
R. (20mL of 0.1 M HCl+20mL of 0.1 M ammonia solution) diluted to 80ML	3. the value of $[\mathrm{H}^{+}]$ changes to two times of its initial value on dilution
S. 10mL saturated solution of $\mathrm{Ni}(\mathrm{OH})_2$ in equilibrium with excess solid $\mathrm{Ni}(\mathrm{OH})_2$ is diluted to 20mL (solid $\mathrm{Ni}(\mathrm{OH})_2$ is still present after dilution)	4. the value of $[\mathrm{H}^{+}]$ change to $\frac{1}{\sqrt{2}}$ times of its initial value on dilution
	5. he value of $[\mathrm{H}^{+}]$ changes to $\sqrt{2}$ times of its initial value on dilution

Solution:

\underset{\text{0.1M 20ml}}{\mathrm{CH}_3\mathrm{COOH}}+\underset{\text{0.1M.10ml}}{\mathrm{NaOH}}\rightarrow\mathrm{CH}_3\mathrm{COONa}+\mathrm{H}_2\mathrm{O}

\mathrm{pH}=\mathrm{pKa}\Rightarrow[\mathrm{H}^{+}]

will not change on dilution correct match:

P-1

\underset{\text{0.1M,20ml}}{\mathrm{CH}_3\mathrm{COOH}}+\underset{\text{0.1M.20ml}}{\mathrm{NaOH}}\rightarrow\mathrm{CH}_3\mathrm{COONa}+\mathrm{H}_2\mathrm{O}

–– –– 0.05 M

[\mathrm{OH}^{+}]=\sqrt{K_HC}=\sqrt{\frac{k_w}{k_aC}}

[\mathrm{H}^{+}]=\sqrt{\frac{k_w k_a}{C}}

\frac{[\mathrm{H}^{+}]_2}{[\mathrm{H}^{+}]_1}\sqrt{\frac{C_1}{C_2}}\sqrt{\frac{0.05}{0.025}}\sqrt{2}

correct match: Q-5

\underset{\text{0.1M,20ml}}{\mathrm{NH}_4\mathrm{OH}}+\underset{\text{0.1M,20ml}}{\mathrm{HCl}}\rightarrow\underset{\text{0.05M}}{\mathrm{NH}_4\mathrm{Cl}}

[\mathrm{H}^{+}]=\sqrt{K_HC}

\frac{[\mathrm{H}^{+}]_2}{[\mathrm{H}^{+}]_1}=\sqrt{\frac{C_2}{C_1}}=\frac{1}{\sqrt{2}}

correct match: R- 4

S. Because of dilution solubility does not change so

[\mathrm{H}^{+}]

= constant

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