21but govind i t have read it somewhere in ncert that Cu is more stable in +2 oxidation state than in +1 oxidation state........so shouldnt the answer be C?
1)excess KCN is added to cupric salt and H2S is passed through the solution. no black CuS is precipitated because Cu is present in the solution as
a)[Cu(CN)6]4-
B)[Cu(CN)4]3-
C)[Cu(CN)4]2-
D)NONE.
2)Co3+ forms a complex with F- ion. the complex had a magnetic moment of 4.8BM. the hybridisation and geometry of the complex would be?
-
UP 0 DOWN 0 0 4
4 Answers
29the answer is B..I read it in JD LEE that the compound given in B is soluble...
2129@saket wat u have read is right... Cu2+ is more stable than Cu+..and that's becsuse of the greater hydration energy released in case of Cu2+ ..but here in this case we have [Cu(CN)4]2- and [Cu(CN)4]3- ...more hydration energy will be released in case of [Cu(CN)4]3-..that may be the reason but i am not sure abt it...
Another example Au exists in +1 and +3 oxidation states..and +3 oxidation state is more stable..but wen Au forms complex with CN- (U may have read abt the complex in metallurgy chapter in the NCERT under the topic leaching and extraction of gold and silver) ..it exists in +1 oxidation state..
PS: Sometimes in inorganic it happens when u think logically u may get the wrong answer..but u shudnt feel disheartened...u shud learn frrom the mistake....coz inorganic chemistry is all abt learning and practicing more and more questions...