Sulfur dioxide gas turns acidified potassium dichromate solution from orange to green reduced chromium +4 to +3.
K2Cr2O7 + 2H2SO4 + 3SO2 → 2Cr2(SO4)3 + K2SO4 + H2O
Write an ionic equation representing the oxidising property of acidified potassium permanganate solution.
i)When the aqueous solution of potassium dichromate is treated with calculated amount of KOH, potassium chromate is formed.
K2Cr7O7 + 2KOH → 2K2CrO4 + H2O
ii) When an alkali is added to an orange red solution containing dichromate ions, a yellow solution is obtained due to the formation of chromate ions.
K2Cr2O7 + K2CO3 → 2 K2CrO4 + CO2