Question
Which of the following statements is incorrect ?
A.
$$F{e^{2 + }}\,ion$$ also gives blood red colour with $$SC{N^ - }\,ion.$$
B.
$$F{e^{3 + }}\,ion$$ also gives blood red colour with $$SC{N^ - }\,ion.$$
C.
On passing $${H_2}S$$ into $$N{a_2}Zn{O_2}$$ solution a white ppt of $$ZnS$$ is formed.
D.
Cupric ion reacts with excess of ammonia solution to give deep blue colour of $${\left[ {Cu{{\left( {N{H_3}} \right)}_4}} \right]^{2 + }}\,ion.$$
Answer :
$$F{e^{2 + }}\,ion$$ also gives blood red colour with $$SC{N^ - }\,ion.$$
Solution :
Only $$F{e^{3 + }}\,ion$$ give blood red colouration with $$SC{N^ - }\,ions.$$
$$F{e^{3 + }} + SC{N^ - } \to \mathop {{{\left[ {Fe\left( {SCN} \right)} \right]}^{2 + }}}\limits_{{\text{(dark red)}}} $$