Question

Identify the correct statements about the following stoichiometric equation. \[ aP_4 + bOH^- + CH_2O \rightarrow dPH_3 + eH_2PO_2^- \]
[I.] \(a + b + c = 5\)
[II.] \(b + c - e = 3\)
[III.] The oxidation state of P in \(H_2PO_2^-\) is \(+1\)

• A. I, II, III
• B. I, II only
• C. I, III only
• D. II, III only

Hint:

To determine oxidation states, always balance the total oxidation numbers with the overall charge of the molecule or ion.

Answer 1

The Correct Option is D

Step 1: Analyze the given chemical equation
The given reaction is: \[ aP_4 + bOH^- + CH_2O \rightarrow dPH_3 + eH_2PO_2^- \] Step 2: Understand the balancing conditions
From stoichiometric balancing: - Statement I: \(a + b + c = 5\) is incorrect upon checking the balanced equation. - Statement II: \(b + c - e = 3\) is found to be valid based on balancing. - Statement III: In \(H_2PO_2^-\), using oxidation number method: \[ (+1 \times 2) + x + (-2 \times 2) = -1 \Rightarrow 2 + x - 4 = -1 \Rightarrow x = +1 \] So, the oxidation state of phosphorus is \(+1\), making the statement true. Step 3: Conclusion
Only statements II and III are correct.