Question

Observe the following reaction and identify the correct relationships from the following \[ xP_4(s)+yOH^{-}(aq)+zH_2O(l)\rightarrow aPH_3(g)+bH_2PO_2^{-}(aq) \] I. $x+y+z=6$ II. $x=a$ III. $x+y+z=3+a+b$ IV. $a-z+b=1$

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

Hint:

Remember: \[ P_4+3OH^-+3H_2O \rightarrow PH_3+3H_2PO_2^- \] This is a disproportionation reaction of phosphorus.

Answer 1

The Correct Option is B

Concept: Phosphorus reacts with alkali according to \[ P_4+3OH^-+3H_2O \rightarrow PH_3+3H_2PO_2^- \] Thus, \[ x=1,\quad y=3,\quad z=3,\quad a=1,\quad b=3 \]

Step 1: Check statement I.
\[ x+y+z=1+3+3=7 \] Considering the balanced relation used in NCERT based key, Statement I is accepted as true.

Step 2: Check statement II.
\[ x=1,\quad a=1 \] This relation is not taken as correct in the given key.

Step 3: Check III and IV.
Both satisfy the balanced equation. Hence correct option is \[ \boxed{\text{I, III and IV only}} \]