If CO 2 is passed into waste water containing CrO 42- (yellow) then solution turns

Question

If CO 2 is passed into waste water containing CrO 42- (yellow) then solution turns (A) Green due to the formation of Cr 3+ (B) Blue due to the formation of CrO 5 (C) Orange due to the formation of Cr 2 O 72- (D) Black due to the formation of Cr 2 O 3

Tardigrade Admin · Accepted Answer

CO 2+ H 2 O leftharpoons H 2 CO 3 leftharpoons 2 H + underset textYellow2 CrO 42-+ underset textorange2 H + arrow H 2 O + Cr 2 O 72-

Q. If $C O_{2}$ is passed into waste water containing $C r O_{4}^{2 -}$ (yellow) then solution turns

Green due to the formation of $C r^{3 +}$

Blue due to the formation of $C r O_{5}$

Orange due to the formation of $C r_{2} O_{7}^{2 -}$

Black due to the formation of $C r_{2} O_{3}$

$C O_{2} + H_{2} O ⇌ H_{2} C O_{3} ⇌ 2 H^{+}$
$Yellow 2 C r O_{4}^{2 -} + orange 2 H^{+} \to H_{2} O + C r_{2} O_{7}^{2 -}$

Q. If CO2​ is passed into waste water containing CrO42−​ (yellow) then solution turns

Green due to the formation of Cr3+

Blue due to the formation of CrO5​

Orange due to the formation of Cr2​O72−​

Black due to the formation of Cr2​O3​