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Answer the following.
Complete the following chemical equations: _______ _______ _______
Complete the following chemical equations:
(i)[1.0]
$\text{K}_2\text{Cr}_2\text{O}_7 + \text{H}_2\text{SO}_4 + \text{FeSO}_4 \rightarrow$ _______
(ii)[1.0]
$\text{K}_2\text{Cr}_2\text{O}_7 + \text{H}_2\text{SO}_4 + \text{H}_2\text{S} \rightarrow$ _______
(iii)[1.0]
$\text{KMnO}_4 + \text{H}_2\text{SO}_4 + \text{H}_2\text{C}_2\text{O}_4 \rightarrow$ _______
Answer
Answer (i)
AIEquation: $\mathrm{K_{2}Cr_{2}O_{7}} + 7\mathrm{H_{2}SO_{4}} + 6\mathrm{FeSO_{4}} \longrightarrow \mathrm{K_{2}SO_{4}} + \mathrm{Cr_{2}(SO_{4})_{3}} + 3\mathrm{Fe_{2}(SO_{4})_{3}} + 7\mathrm{H_{2}O}$
$\mathrm{K_2Cr_2O_7 + 7H_2SO_4 + 6FeSO_4 \rightarrow K_2SO_4 + Cr_2(SO_4)_3 + 3Fe_2(SO_4)_3 + 7H_2O}$
Answer (ii)
AIEquation: $\mathrm{K_{2}Cr_{2}O_{7}} + 4\mathrm{H_{2}SO_{4}} + 3\mathrm{H_{2}S} \longrightarrow \mathrm{K_{2}SO_{4}} + \mathrm{Cr_{2}(SO_{4})_{3}} + 3\mathrm{S} + 7\mathrm{H_{2}O}$
Hydrogen sulphide is oxidised to sulphur.
Answer (iii)
AIEquation: $2\mathrm{KMnO_{4}} + 3\mathrm{H_{2}SO_{4}} + 5\mathrm{H_{2}C_{2}O_{4}} \longrightarrow \mathrm{K_{2}SO_{4}} + 2\mathrm{MnSO_{4}} + 10\mathrm{CO_{2}} + 8\mathrm{H_{2}O}$
Oxalic acid is oxidised to carbon dioxide.
From ISC 2018 Specimen Chemistry Paper 1, question 13(b).