In coordination chemistry there are a variety of methods applied to find out the structure of complexes.One method involves treating the complex with known reagents and from the nature of reaction, the formula of the complex can be predicted.An isomer of the complex `Co(en)_2(H_2O)Cl_2Br`,on reaction with concentrated `H_2SO_4` (dehydrating agent) it suffers loss in weight and on reaction with `AgNO_3` solution it gives a white precipitate which is soluble in `NH_3`(aq).
If one mole of original complex is treated with excess `Pb(NO_3)_2` solution, then the number of moles of white precipitate (of `PbCl_2`) formed will be :

Options

A. 0.5
B. `1.0`
C. `0.0`
D. `3.0`

Answer

A

Explanation

Complex contains one `Cl^-` as counter ion.
One mole of complex=one mole of `Cl^-`
As two mole of `Cl^-` gives one mole of `PbCl_2`
`therefore` One mole of `Cl^-` will give 1/2 mole of `PbCl_2`