Assertion & Reason Test: Equilibrium - NEET MCQ

The bond strength of an acid generally depends on the size of the ′A′ atom: the smaller the ′A′ atom, the stronger the H−A bond. When going down a row in the Periodic Table, the atoms get larger so the strength of the bonds get weaker, which means the acids get stronger.
While comparing acids formed by the elements belonging to the same group of periodic table, ′A′ bond strength is a more important factor in determining acidity of an acid than the polar nature of the bond.
So, the correct option is A) Both Assertion and Reason are correct and Reason is the correct explanation for Assertion

Correct explanation. HCl gives the common H⁺ ions and hence ionization equilibrium H₂S⇔2H⁺+S²⁻ is suppressed.

The correct option is A
Both A and R are true and R is the correct explanation of A.
Analyzing the assertion
It is correct because aqueous solution of ammonium carbonate is basic in nature.
Analyzing the reason
It is also correct because for a solution of salt of weak acid and weak base, the acidic/basic nature depends upon value of K_a for weak acid and K_b for weak base.
Solution is basic if
K_b (weak base) >K_a (weak acid).
Ka(H₂CO₃)=4.3×10⁻⁷
Kb(NH₄OH)=1.8×10⁻⁵
K_b (Ammonium hydroxide) >Ka (Hydrogen carbonate)
∴ Hence, solution of Ammonium carbonate is basic in nature.
Both A and R are true and R is the correct explanation of A.
∴ Correct answer is option (A).

Analyzing the assertion

It is false.

PCl₅(g)⇌PCl₃(g)+Cl₂(g)

When an inert gas (He) is added to the system in equilibrium at constant pressure, then the total volume will increase. Hence, the number of moles per unit volume of various reactants and products will decrease.

Hence, the equilibrium will shift towards the direction in which there is increase in number of moles of gases. i.e. forward direction. So, it will facilitate or increase the dissociation of PCl₅. and statement given in assertion is correct.

Analyzing the reason

Helium removes Cl₂ from the field of action.

It is false statement. Helium does not react withCl₂, therefore it cannot remove Cl₂ from the reaction mixture.

A is true, R is false

The correct option is A
Both A and R are true and R is the correct explanation of A.
Analyzing the assertion
Given solution of CH3COOH and CH3COONa maintain constant value of pH on addition of small amount of acid or alkali. Yes, it is correct statement
Analyzing the reason
Since, it is an acidic buffer, because it is prepared from weak acid (i.e. acetic acid) and its salt with strong base (i.e. Sodium Acetate).
Buffer solution resists change in pH value.
Since this is acidic buffer,.
So, the buffer range will be observed at pH of around
pH≈pKa (pKa=4.75,for acetic acid)
So, the statement given in reason is correct and it explain the assertion too. Hence,
∴ Both assertion and reason are true and reason is the correct explanation of assertion.
Therefore, correct answer is option (A).

The correct option is C
A is true but R is false.
Analyzing the assertion
For any chemical reaction at a particular temperature the equilibrium constant is fixed and is a characteristic property
It is correct, because for a given chemical reaction its equilibrium constant K does have fixed value at constant temperature, which is characteristic property because it gives information about the extent of reaction at equilibrium.
Analyzing the reason
Equilibrium constant is independent of temperature.
It is incorrect, because the value of equilibrium constant (K) is temperature dependent and its value is different at different temperatures for a same chemical reaction.
Equilibrium constant is the ratio of rate constants of forward and backward reaction. Since, rate constant depends upon temperature (as per Arrhenius equation, k=Ae−Ea/RT). So, equilibrium constant will also depend on temperature.
Assertion is correct, but Reason is incorrect (false)
∴ So, Correct option is (C).

Analyzing the Assertion and Reason:
Assertion : It is true because solution of ammonium acetate is salt solution giving NH⁺⁴ and CH₃COO⁻ ions which can react with both H⁺ and OH⁻ from strong acid or base in a small amount to form weak acid or base so will resist the change in pH, so it is a buffer solution.

Reason : It is not because CH₃COOH is weak acid and NH₄OH is a weak base as explained above.
Hence A is false but R is true.

(ii) Solid ⇌ Liquid equilibrium exists at the melting point.

(iii) Solid ⇌ Vapour equilibrium exists at the sublimation point.

(iv) Solute(s) ⇌ Solute (solution) equilibrium exists in saturated solution.

(ii) For spontaneous reaction, ΔG < 0(−ve), K > 1. Hence (ii)-(d).

(iii) For non-spontaneous reaction, ΔG > 0(+ve), K < 1. Hence (iii) - (a).

• According to Le chatelier's principle as the time passes accumulation of products occur and depletion of reactant i.e. reaction will proceed in the forward direction.

• According to Le chatelier's principle as time passes accumulation of reactant occurs and depletion of product i.e. the reaction will proceed in the backward direction.

• According to Le chatelier's principle as time passes equal attainment of reactant and product occurs and chemical Equilibrium is obtained. It can be obtained from either direction.