Question

$Fe^{3+}$ can be used for coagulation of $As_2S_3$ sol. $Fe^{3+}$ reacts with $As_2S_3$ to give $Fe_2S_3$.

• A. If both assertion and reason are true and reason is the correct explanation of assertion
• B. If both assertion and reason are true but reason is not the correct explanation of assertion
• C. If assertion is true but reason is false
• D. If both assertion and reason are false

Answer 1

Answer: (C)

If assertion is true but reason is false

Answer 2

Because of iron's strong affinity to arsenic (As), iron-based coagulants such as ferric sulfate and ferric chloride are more effective when it comes to removing arsenic (As) from water. In addition, iron hydroxides are less prone to go into solution in environments ranging from $5.5$ to $8.5$ in $pH$. Iron salts can thus be used for coagulation of arsenic sol. $e 3+ Fe ^{3+}$ neutralizes the charge on the negatively charged $As _{2} S _{3}$ particles but does not react to give $Fe _{2} S _{3} .$ Therefore, the Assertion is correct but Reason is incorrect