Question

The most alkaline hydroxide among the following is La(OH)3 Pr(OH)3 Gd(OH)3 Er(OH)3

Answer 1

Answer:

The correct answer is.

La(OH)3> Pr(OH)3> Gd(OH)3> Er(OH)3

Explanation:

Basicity decreases along the lanthanide series.

PLEASE MARK AS BRAINLIEST ANSWER IF YOU FIND IT HELPFUL

Answer 2

Answer:(D)

Explanation:

Complete step by step answer:

The lanthanides, also known as lanthanons are a group of 15 elements of atomic numbers starting from 57 to 71 in which scandium (atomic number 21) and yttrium (atomic number 39) are sometimes included. Due to lanthanide contraction, the size of M3+

ions (that is, Lu3+

, Eu3+

, Yb3+

and Ce3+

) decreases and thus, the basic strength of their hydroxides decreases. The order of size of given M3+

ions is Ce3+>Eu3+>Yb3+>Lu3+

and as the size of lanthanide ions decreases from La3+

to Lu3+

and the covalent character of the hydroxides most often increases and thus the basic strength of hydroxides decreases. Therefore, La(OH)3, being the most basic and Lu(OH)3 being the least basic of all.

As we know that, the order of basic strength of hydroxides from the least basic hydroxide to the most basic is Ce(OH)3>Eu(OH)3>Yb(OH)3>Lu(OH)3.

Therefore, the correct answer is option (D).