Question

Which one of the following when dissolved in water gives coloured solution in nitrogen atmosphere ?

JEE MAINS 2021

• A. $CuC{l}_2$
• B. $ZnC{l}_2$
• C. $C{u}_{2}C{l}_2$
• D. $AgCl$

Answer 1

The correct option is A $CuC{l}_2$

$CuC{l}_2$ in water gives blue solution .

$\left(1\right)CuC{l}_2+n{H}_{2}O\to C{u}^{2+}(aq.)$
$bluecolour$
Electronic configuration of $C{u}^{2+}$ is $3d^9$. Thus, it will have unpaired electrons so, it shows colour.

$\left(2\right)AgCl+n{H}_{2}O\to Insoluble$

$\left(3\right)ZnC{l}_2+n{H}_{2}O\to Z{n}^{2+}(aq.)$
$Colourless$
Electronic configuration of $Z{n}^{2+}$ is $3d^{10}$. Thus, it does mot have unpaired electrons so, it wont shows colour.

Hence, option (d) is correct.
$\left(4\right)C{u}_{2}C{l}_2+n{H}_{2}o\to Insoluble$