JEE Main20252 Apr 2025Morning ShiftChemistryElectrochemistryActual
Consider the following electrochemical cell at standard condition. ( aligned & Au ( s ) | QH ₂, Q | NH ₄ X (0.01 M )| | Ag ⁺(1 M ) Ag ( s ) & E _ cell =+0.4 ~V aligned ) The couple ( QH ₂ / Q ) represents quinhydrone electrode, the half cell reaction is given below The ( pK _ b ) value of the ammonium halide salt ( ( NH ₄ X ) ) used here is _________. (nearest integer)
Correct answer
0
Step-by-step solution
( aligned & QH ₂+2 Ag ⁺ 2 Ag + Q +2 H ⁺ & E = E ^ - 0.06 2 [ H ⁺ ]^2 & E = E ^ -0.06 [ H ⁺ ] & pH =- ( H ⁺ )= E - E ^ o 0.06 = 0.4-0.1 0.06 & = 0.3 0.06 =5 aligned ) ( aligned & pH + NH ₄ X =7- 1 2 pK _ b - 1 2 C & 5=7- 1 2 pK _ b - 1 2 (10⁻² ) & pK _ b =6 aligned )