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Equilibrium

JEE Main 2025 (Online) 23rd January Morning ShiftMCQMedium📈 Topic in 21% papers+4−1
Ques. 1JEE Main 2025, 23 January (Morning Shift)

Which of the following happens when NH4OH is added gradually to the solution containing 1 M A2+ and 1M B3+ ions? Given : Ksp [A(OH)2] = 9 10-10 and Ksp [B(OH)3] = 27 10-18 at 298 K.

  1. A(OH)2 will precipitate before B(OH)3
  2. A(OH)2 and B(OH)3 will precipitate together
  3. Both A(OH)2 and B(OH)3 do not show precipitation with NH4OH
  4. B(OH)3 will precipitate before A(OH)2

Answer

(4) B(OH)3 will precipitate before A(OH)2

Solution

Concept: the hydroxide needing the smaller [OH-] precipitates first.

A(OH)2: [OH-] = 9 10-10 = 3 10-5 M

B(OH)3: [OH-] = (27 10-18)1/3 = 3 10-6 M

3 10-6 < 3 10-5 ⇒ B(OH)3 precipitates first.

Answer: (4)

Keep practising — Equilibrium

Ques. 2JEE Main 2025, 23 January (Morning Shift)

If 1 mM solution of ethylamine produces pH=9, then the ionization constant (Kb) of ethylamine is 10-x. The value of x is (nearest integer). [The degree of ionization of ethylamine can be neglected with respect to unity.]

Ques. 3JEE Main 2025, 23 January (Evening Shift)

pH of water is 7 at 25 C. If water is heated to 80 C, it's pH will :

  1. Decrease
  2. Remains the same
  3. Increase
  4. H+ concentration increases, OH- concentration decreases
Ques. 4JEE Main 2025, 23 January (Evening Shift)

Consider the reaction X2Y(g) X2(g) + 12Y2(g) The equation representing correct relationship between the degree of dissociation (x) of X2Y(g) with its equilibrium constant Kp is . Assume x to be very very small.

  1. x = [3] KpP
  2. x = [3] Kp2P
  3. x = [3] 2 Kp2P
  4. x = [3] 2KpP
Ques. 5JEE Main 2025, 22 January (Morning Shift)

A vessel at 1000 K contains CO2 with a pressure of 0.5 atm. Some of CO2 is converted into CO on addition of graphite. If total pressure at equilibrium is 0.8 atm, then Kp is :

  1. 0.18 atm
  2. 0.3 atm
  3. 3 atm
  4. 1.8 atm
Ques. 6JEE Main 2025, 22 January (Evening Shift)

The molar solubility(s) of zirconium phosphate with molecular formula ( Zr4+ )3 ( PO43- )4 is given by relation :

  1. ( Ksp5348 )1/6
  2. ( Ksp8435 )1/7
  3. ( Ksp6912 )1/7
  4. ( Ksp9612 )1/3

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