Question

Which of the following is arranged in the order of increasing radius of ions in aqueous solution?

• A. $Li ^{+}< Na ^{+}< K ^{+}< Rb ^{+}< Cs ^{+}$
• B. $Cs ^{+}< Rb ^{+}< K ^{+}< Na ^{+}< Li ^{+}$
• C. $Rb ^{+}< Na ^{+}< Li ^{+}< Cs ^{+}< K ^{+}$
• D. $Cs ^{+}< K ^{+}< Rb ^{+}< Li ^{+}< Na ^{+}$

Answer 1

Answer: (B)

$Li ^{+}$has highest hydration enthalpy.
Hence it is most hydrated
$\therefore $ Correct order of hydrated radii is
$Cs ^{+}< Rb ^{+}< K ^{+}< Na ^{+}< Li ^{+}$