Question

In the extraction of iron from haematite, the impurity (x) of the ore is removed in the form of 'y'.
What are x and y respectively?

• A. SiO$_2$, CaSiO$_3$
• B. CaO, CaSiO$_3$
• C. SiO$_2$, FeSiO$_3$
• D. P$_2$O$_5$, Ca$_3$(PO$_4$)$_2$

Hint:

During iron extraction, acidic impurities like SiO$_2$ are removed by forming a fusible slag (CaSiO$_3$) with basic fluxes like CaO.

Answer 1

The Correct Option is A

Step 1: Identify the impurity in haematite. 
The main impurity in the extraction of iron from haematite (Fe$_2$O$_3$) is silica (SiO$_2$). 
Step 2: Role of limestone (CaCO$_3$). 
When heated, CaCO$_3$ decomposes to give CaO, which acts as a basic flux: \[ \text{CaCO}_3 \rightarrow \text{CaO} + \text{CO}_2 \] Step 3: Formation of slag. 
The CaO reacts with SiO$_2$ (acidic impurity) to form calcium silicate (CaSiO$_3$), which is the slag: \[ \text{CaO} + \text{SiO}_2 \rightarrow \text{CaSiO}_3 \] Thus, impurity \(x\) is SiO$_2$ and it is removed as \(y = \text{CaSiO}_3\).