Question

Consider the following reactions:

$A_x + yB_2 \xrightarrow[supply \ of \ air]{limited} compound \ 'P' \xrightarrow[excess \ air]{+zB_2} Compound \ 'Q'$

If atomic number of elements A and B are 15 and 8 respectively, then according to the given information the correct statements(s) is / are:

• A. (B-A-B) bond angle in compound 'Q' > (B-A-B) bond angle in compound 'P'
• B. (A-B) bond length in compound 'Q' < (A-B) bond length in compound 'P'
• C. Value of x + y + z is 9
• D. Compound 'P' is $P_2O_5$ and compound 'Q' is $P_4O_{10}$

Answer 1

Answer: (B)

b

Answer 2

Elements A and B are identified as Phosphorus (P) and Oxygen (O) respectively based on their atomic numbers. The reactions show that phosphorus reacts with limited oxygen to form $P_4O_6$ (compound 'P') and with excess oxygen to form $P_4O_{10}$ (compound 'Q'). The values of x, y, and z are determined from the balanced equations as $x=4$, $y=6$, and $z=2$. Statement (c) is incorrect as $x+y+z=12 \neq 9$. Statement (d) is incorrect because 'P' is $P_4O_6$, not $P_2O_5$. Statement (a) is incorrect as the O-P-O bond angles in $P_4O_{10}$ are not consistently greater than those in $P_4O_6$. Statement (b) is correct because $P_4O_{10}$ contains shorter P=O double bonds (approx. 143 pm) compared to the P-O single bonds in $P_4O_6$ (approx. 165 pm).