Question

Yellow coloured aqeous solution of sodium chromate changes to orange when acidified with sulphuric acid because

• A. $H^{+}$ions convert chromate ions to dichromate ions
• B. $H^{+}$ions react with sodium chromate to give sodium ions which turn solution orange
• C. $Cr^{3 +}$ions are liberated in the solution which turn the solution orange.
• D. Sodium hydroxide is formed during the reaction which imparts orange colour to the solution.

Answer 1

Answer: (A)

$H^{+}$ions convert chromate ions to dichromate ions

Answer 2

$\underset{\begin{aligned} & Yellowcoloured \\ & solution \end{aligned}}{2Na_{2}CrO_{4}} + 2H^{+} \rightarrow \underset{\begin{aligned} & Orangecoloured \\ & solution \end{aligned}}{Na_{2}Cr_{2}O_{7}} + 2Na^{+} + H_{2}O$