Among lanthanoids, Ln (III) compounds are predominant. However, occasionally in solutions on in solid compounds, + 2 and +4 ions are also obtained.

Ionic compounds are insulators when in solid state whereas when in aqueous solution they become conductors why?

When orange solution containing Cr_2O_7^(2-) ion is treated with an alkali, a yellow solution is formed and when H^+ ions are added to yellow solution, an orange solution is obtained. Explain why does this happen ?

Write the oxidation number of central atom of following compound : [Co Cl_2 (en)_2 ]SO_4

Ammonia forms the complex ion [Cu(NH_3)_4]^(2+) with copper ions in alkaline solutions but not in acidic solution. The reason for this is

Compound ‘A’ with molecular formula C_4H_9Br is treated with aq. KOH solution. The rate of this reaction depends upon the concentration of the compound ‘A’ only. When another optically active isomer ‘B' of this compound was treated with aq. KOH solution, the rate of reaction was found to be dependent on concentration of compound and KOH both. Out of these two compounds, which one will be converted to the product with inverted configuration.

Compound ‘A’ with molecular formula C_4H_9Br is treated with aq. KOH solution. The rate of this reaction depends upon the concentration of the compound ‘A’ only. When another optically active isomer ‘B' of this compound was treated with aq. KOH solution, the rate of reaction was found to be dependent on concentration of compound and KOH both. Write down the structural formula of both compounds ‘A’ and 'B’.

Write the oxidation number of central atom of following compound : [Co Cl_2 (en)_2 ]_2 SO_4

Write the oxidation number of central atom of following compound : [Co (en)_2 F_2 ]ClO_4

What is the coordinate number of the central metal ions in the following coordination compound ? [PtCl_2(en)_2]

Write the ligands of coordination entities and counter ions in the following coordination compound : K_2[PtCl_4]