31 Year NEET Previous Year Questions: Equilibrium - 3 - NEET MCQ

NaCl is a salt of strong acid and strong base hence its aqueous solution will be neutral ie pH = 7. NaHCO₃ is an acidic salt hence pH < 7 . Na₂CO₃ is a salt of weak acid and strong base. Hence its aqueous solution will be strongly basic ie. pH > 7.
NH₄Cl is salt of weak base and strong acid, hence its aqueous solution will be strongly acidic i.e. pH < 7.

For reation (1)

and for reaction (2)

An aqueo us solution of acetic acid dissociates as

Sodium borate is a salt of strong base (NaOH) and weak acid (H₃BO₃). Hence its aqueous solution will be basic

According to Le-ch atelier's principle" whenever a constraint is applied to a system in equilibrium, the system tends to readjust so as to nullify the effect of the constraint.

AgBr has the highest solubility in 10^-3 M NH₄OH . All other solven ts will dissolve AgBr poorly. Moreover bromides of Ag⁺, Hg₂²⁺ and Cu₂²⁺ are water insoluble

It is an endothermic process. So when temperature is raised, more liquid is formed.
Hence adding heat will shift the equilbrium in the forward direction.

In presence of the given salts, the solubility of AgCl decreases due to common ion effect.

For Bi₂S₃ .   K_sp– = (2s)².(3s)³                              
= 4s². 27s³ = 108s⁵

or     

For MnS. K_sp = s²

thus MnS has maximum solubility.

Molarity (M) = 10M. HCl is a str ong acid and it is completely dissociated in aqueous solutions as :
So, for every moles of HCl, there is one H⁺.
Therefore [H⁺] = [HCl] or [H⁺] = 10. pH = – log[H⁺] = – log [10] = – 1.

Rate constant of forward reaction (K_f) = 1.1 × 10^–2 and rate constant of backward reaction (K_b) = 1.5 × 10^–3 per minute. Equilibrium constant  

The buffer system present in serum is H₂CO₃ + NaHCO₃ and as we known that a buffer solution resist the change in pH therefore pH value of blood does not change by a small addition of an acid or a base.

According to equation

Total moles at equilibrium = 2 – 2α +α+α = 2 mole

Equilibrium constant is given by

Since the value given is very small, hence conc. of products is less. It means the reaction is slow.

For Binary salts like CuS & HgS, solubilty,

∴ The order is CuS > Ag₂S > HgS

For small concentration of buffering agent and for maximum buffer capacity

∴ pH = pK_a

since the steps 1 and 2 are exothermic hence low temprature will favour both the reactions.
In step - 1 moles are increasing hence low pressure will favour it. In step 2 moles are decreasing, hence high pressure will favour it.

For the reaction

and for the reaction

For reaction :

∴   From eq. no. (1) and (2)
K = K₂/ K₁

Lewis acid is that compound which have electron deficiency. eg. BF₃, SnCl₂.

No. of moles of NaOH =  = 0.1

[Molecular weight of NaOH = 40]

No. of moles of OH^– = 0.

Concentration of OH^– = 0.1Mole /L

As we know that, [H⁺] [OH^– ] = 10^–14

Solubility product = [x]  [2x]² = 4x³

∴   x = 10^–4

Given : Hydroxyl ion concentration [OH^–] = 0.05 mol L^–1. We know that the 

 We also know that

Since the value of pH > 7, therefore the solution is basic.

MgCO₃(s) → MgO(s) + CO₂(g) MgO & MgCO₃ are solid and they donot exert any pressure and hence only pressure exerted is by CO₂. Therefore K_P = P_CO₂

Because NH₃ after losing a proton (H⁺) gives NH₂^–

(Conjugate acid-base pair differ only by a proton)

In polyprotic acids the loss of second proton occurs much less readily than the first.
Usually the K_a values for successive loss of protons from these acids differ by at least a factor of 10^–3 i.e.,  

CH₃COOH is weak acid while NaOH is strong base, so one equivalent of NaOH can not be neutralized with one equivalent of CH₃COOH.
Hence the solution of one equivalent of each does not have pH value as 7. Its pH will be towards basic side as NaOH is a strong base hence conc. of OH^– will be more than the conc. of H⁺.

Solubility product = (2x)² (x) = 4x³ = 4 (3.5 × 10^–6)³  = 1.7 × 10^–16

Given that,

CH₃COOH is weak acid, so in it [CH₃COOH] is equal to initial concentration. Hence

= 6.8 × 10^–3M

Strong base has higher tendency to accept the proton. Increasing order of base and hence the order of accepting tendency of proton is I^- < HS^- < NH₃ < RNH₂

For the reaction

At equilibrium

[For solid and liquids concentration term is taken as unity]
Hence, the value of equilibrium constant depends only upon partial pressure of O₂.
Further on increasing temperature formation of O₂ increases as this is an endothermic reaction.