Question

The molar mass of the water insoluble product formed from the fusion of chromite ore \(FeCr_2\text{O}_4\) with \(Na_2\text{CO}_3\) in presence of \(O_2\) is ....... g mol\(^{-1}\):

Answer 1

Correct Answer: 160

To solve this problem, we need to identify the insoluble product formed in the reaction and then calculate its molar mass.

1. Identifying the Reaction:
Chromite ore ($FeCr_2O_4$) reacts with sodium carbonate ($Na_2CO_3$) and oxygen ($O_2$) to form sodium chromate ($Na_2CrO_4$), iron(III) oxide ($Fe_2O_3$), and carbon dioxide ($CO_2$).
The balanced chemical equation is: $4FeCr_2O_4(s) + 8Na_2CO_3(s) + O_2(g) \rightarrow 8Na_2CrO_4(aq) + 2Fe_2O_3(s) + 8CO_2(g)$

2. Identifying the Insoluble Product:
From the reaction, sodium chromate is soluble, while iron(III) oxide ($Fe_2O_3$) is insoluble.

3. Calculating the Molar Mass of $Fe_2O_3$:
Given: Molar mass of Fe = 56 g/mol
Molar mass of O = 16 g/mol
Molar mass of $Fe_2O_3$ = (2 × Molar mass of Fe) + (3 × Molar mass of O) = (2 × 56 g/mol) + (3 × 16 g/mol) = 112 g/mol + 48 g/mol = 160 g/mol

Final Answer:
The molar mass of the insoluble product $Fe_2O_3$ is 160 g/mol.