The Sblock Elements Ques 49
49. The correct order of the mobility of the alkali metal ions in aqueous solutions is
[2006]
(a) $Na^{+}>K^{+}>Rb^{+}>Li^{+}$
(b) $K^{+}>Rb^{+}>Na^{+}>Li^{+}$
(c) $Rb^{+}>K^{+}>Na^{+}>Li^{+}$
(d) $Li^{+}>Na^{+}>K^{+}>Rb^{+}$
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Answer:
Correct Answer: 49.(c)
Solution:
(c) Hydrated Ionic radii of alkali metals in water follows the order $Cs^{+}>Rb^{+}>K^{+}>Na^{+}>Li^{+}$
Thus in aqueous solution due to smaller ionic radius $Li^{+}$has lowest mobility and hence the correct order of ionic mobility is
$ Li^+ < Na^+ < K^+ <Rb^+ $
BETA
