Sulphide ores are converted to oxides before reduction. This process is called roasting. For example:
\[ 2\text{ZnS} + 3\text{O}_2 \rightarrow 2\text{ZnO} + 2\text{SO}_2 \]
This statement is true.
Oxide ores are generally easier to reduce than sulphide ores. This can be explained by the following:
The reaction for sulphide reduction is:
\[ 2\text{MS} + \text{C} \rightarrow 2\text{M} + \text{CS}_2 \]
Since \( \text{CO}_2 \) is more volatile compared to \( \text{CS}_2 \), oxide reduction is favored. This statement is also true.
Final Answer: Both Statement I and Statement II are correct.
If the system of equations \[ (\lambda - 1)x + (\lambda - 4)y + \lambda z = 5 \] \[ \lambda x + (\lambda - 1)y + (\lambda - 4)z = 7 \] \[ (\lambda + 1)x + (\lambda + 2)y - (\lambda + 2)z = 9 \] has infinitely many solutions, then \( \lambda^2 + \lambda \) is equal to:
The output of the circuit is low (zero) for:

(A) \( X = 0, Y = 0 \)
(B) \( X = 0, Y = 1 \)
(C) \( X = 1, Y = 0 \)
(D) \( X = 1, Y = 1 \)
Choose the correct answer from the options given below:
The metal ions that have the calculated spin only magnetic moment value of 4.9 B.M. are
A. $ Cr^{2+} $
B. $ Fe^{2+} $
C. $ Fe^{3+} $
D. $ Co^{2+} $
E. $ Mn^{2+} $
Choose the correct answer from the options given below
Which of the following circuits has the same output as that of the given circuit?
