MCQ
$Cu(CN)_4^{2 - }$ is colourless as it absorbs light in
- AVisible region
- BUltraviolet region
- CInfrared region
- ✓All above are wrong
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

(Given: Atomic no. $Eu, 63; Sm , 62 ; Tm , 69 ; Tb$, $65 ; Yb , 70 ; Dy , 66]$
