NEET-XII-Chemistry
exam-2 year:2016
- #141Which one of the followng statements related to
lanthanons is incorrect ?
(1) All the lanthanons are much more reactive than
aluminium
(2) Ce(+4) solutions are widely used as oxidizing
agent in volumetric analysis
(3) Europium shows +2 oxidation state.
(4) The basicity decreases as the ionic radius
decreases from Pr to Lu.digAnsr: 1Ans : (1)
Sol. (1) Lanthanon's are less reactive than aluminium due
to high IP (Lanthenoid contraction)
(2) Ce+4 is good oxidising agent and easily converted
into Ce+3
(3) Eu(63) = 4f7 5d0 6s2, Eu+2 = 4f7
(4) In lanthenoids series 'Ce' to Lu ionic radius regular
decreases and covalent character increase, basic
character of hydroxide decrease