Which one of the following forms a colourless solution in aqueous medium?
$$\left( {{\text{At}}{\text{. no}}{\text{.}}\,\,Sc = 21,Ti = 22,} \right.$$ $$\left. {V = 23,Cr = 24} \right)$$
A.
$${V^{3 + }}$$
B.
$$C{r^{3 + }}$$
C.
$$T{i^{3 + }}$$
D.
$$S{c^{3 + }}$$
Answer :
$$S{c^{3 + }}$$
Solution :
The electronic configuration of $$Sc$$ is
$$1{s^2},2{s^2}2{p^6},3{s^2}3{p^6}3{d^1},4{s^2}$$
and configuration of $$S{c^{3 + }}$$ is
$$1{s^2},2{s^2}2{p^6},3{s^2}3{p^6}$$
So, $$S{c^{3 + }}$$ is colourless due to absence of electrons in $$d$$-orbital.
Releted MCQ Question on Inorganic Chemistry >> D and F Block Elements
Releted Question 1
When same amount of zinc is treated separately with excess of sulphuric acid and excess of sodium hydroxide, the ratio of volume of hydrogen evolved is