Question

Three separate vessels (A, B and C) each contain \(100\,\mathrm{mL}\) of distilled water. Some quantity of \(\mathrm{P_4O_{10}(s)}\), \(\mathrm{SiCl_4(l)}\), and \(\mathrm{Ca_3N_2(s)}\) are added into vessels A, B, and C, respectively.  

The pH range in A, B, and C, respectively, is

• A. \(0-7,\;0-7,\;0-7\)
• B. \(0-7,\;0-7,\;7-14\)
• C. \(7-14,\;7-14,\;0-7\)
• D. \(0-7,\;7-14,\;7-14\)

Hint:

Remember these hydrolysis reactions: \[ \boxed{ \mathrm{P_4O_{10}\rightarrow H_3PO_4\ (acidic)} } \] \[ \boxed{ \mathrm{SiCl_4\rightarrow HCl\ (acidic)} } \] \[ \boxed{ \mathrm{Ca_3N_2\rightarrow Ca(OH)_2+NH_3\ (basic)} } \]

Answer 1

The Correct Option is B

Step 1: Identify the nature of the solution in vessel A. \[ \mathrm{P_4O_{10}+6H_2O\rightarrow4H_3PO_4} \] Phosphoric acid is formed. Hence, \[ \boxed{\text{A is acidic (pH }0-7).} \]

Step 2: Identify the nature of the solution in vessel B. \[ \mathrm{SiCl_4+4H_2O\rightarrow Si(OH)_4+4HCl} \] Hydrochloric acid is produced. Hence, \[ \boxed{\text{B is acidic (pH }0-7).} \]

Step 3: Identify the nature of the solution in vessel C. \[ \mathrm{Ca_3N_2+6H_2O\rightarrow3Ca(OH)_2+2NH_3} \] Both calcium hydroxide and ammonia make the solution basic. Hence, \[ \boxed{\text{C is basic (pH }7-14).} \] Therefore, the pH ranges are \[ 0-7,\;0-7,\;7-14. \] Thus, \[ \boxed{(B)} \] is the correct answer.