Test: JEE Main 35 Year PYQs- Equilibrium - JEE

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Thermal decomposition of gaseous X₂ to gaseous X at 298 K takes place according to the following equation:

The standard reaction Gibbs energy, Δ_rG°, of this reaction is positive. At the start of the reaction, there is one mole of X₂ and no X. As the reaction proceeds, the number of moles of X formed is given by β. Thus, β_equilibrium is the number of moles of X formed at equilibrium. The reaction is carried out at a constant total pressure of 2 bar. Consider the gases to behave ideally.

(Given R = 0.083 L bar K^–1 mol^–1)

Q. The INCORRECT statement among the following, for this reaction, is

Each question contains STATEMENT-1 (Assertion) and STATEMENT-2 (Reason). Each question has 5 choices (a), (b), (c) and  (d) out of which ONLY ONE is correct. 

Q. 

Statement -1 The endothermic reactions are favoured at lower temperature and the exothermic reactions are favoured at higher temperature.

Statement -2  When a system in equilibrium is disturbed by changing the temperature, it will tend to adjust itself so as to overcome the effect of change.

Read the following statement and explanation and answer as per the options given below :

Statement -1  HNO₃ is a stronger acid than HNO₂

Statement -2 In HNO₃ there are two nitrogen-to-oxygen bonds whereas in HNO₂ there is only one.

Read the following statement and explanation and answer as per the options given below :

Statement -1 For every chemical reaction at equilibrium, standard Gibbs energy of reaction is zero.

Statement -2 At constant temperature and pressure, chemical reactions are spontaneous in the direction of decreasing Gibbs energy.

1 M NaCl and 1 M HCl are present in an aqueous solution.

The solution is

Species acting as both Bronsted acid and base is

Let the solubility of an aqueous solution of Mg(OH)₂ be x then its K_sp is

Change in volume of the system does not alter  which of the following equilibria?

For the reaction CO (g) + (1/2) O₂ (g) = CO₂ (g), K_p / K_c is

Which one of the following statements is not true? 

The solubility in water of a sparingly soluble salt AB₂ is 1.0 × 10^–5 mol L^–1. Its solubility product number will be

For the reaction equilibrium

the concentrations of N₂O₄ and NO₂ at equilibrium are 4.8 × 10^–2 and 1.2 × 10^–2 mol L^–1 respectively. The value of K_c for the reaction is

Consider the reaction equilibrium

On the basis of Le Chatelier’s principle, the condition favourable for the forward reaction is

When rain is accompanied by a thunderstorm, the collected rain water will have a  pH value

The conjugate base of 

What is the equilibrium expression for the reaction 

For the reaction,  is equal to

The equilibrium constant for the reaction  at temperature T is 4×10^–4.

The value of K_c for the reaction

at the same temperature is

The molar solubility (in mol L^–1) of a sparingly soluble salt MX₄ is ‘s’. The corresponding solubility product is K_sp. ‘s’ is given in term of K_sp by the relation :

If α is the degree of dissociation of Na₂SO₄ , the Vant Hoff’s factor (i) used for calculating the molecular mass is

The solubility product of a salt having general formula MX₂ , in water is : 4 × 10 ^-12. The concentration of M²⁺ ions in the aqueous solution of the salt is

The exothermic formation of CIF₃ is represented by the equation :

Which of the following will increase the quantity of CIF₃ in an equilibrium mixture of Cl₂ , F₂ and ClF₃ ?

For the reaction  

(K_c = 1.8 x 10^-6 at 184°C) (R = 0.0831 kJ/ (mol. K))

When K_p and K_c are compared at 184°C, it is found that

Hydrogenion concentration in mol/L in a solution of pH = 5.4 will be :

What is the conjugate base of OH ^- ?

An amount of solid NH₄ HS is placed in a flask already containing ammonia gas at a certain temperature and 0.50 atm pressure. Ammonium hydrogen sulphide decomposes to yield NH₃ and H₂S gases in the flask. When the decomposition reaction reaches equilibrium, the total pressure in the flask rises to 0.84 atm? The equilibrium constant for NH₄HS decomposition at this temperature is

Phosphorus pentachloride dissociates as follows, in a closed reaction vessel

If total pressure at equilibrium of the reaction mixture is P and degree of dissociation of PCl₅ is x, the partial pressure of PCl₃ will be

The equilibrium constant for the reaction

is K_c = 4.9 × 10^–2. The value of K_c for the reaction

will be

Given the data at 25ºC

What is the value of log K_sp for AgI? (2.303 RT/F = 0.059 V)

The first and second dissociation constants of an acid H,A are 1.0 × 10^–5 and 5.0 × 10^–10 respectively. The overall dissociation constant of the acid will be

The pK_a of a weak acid (HA) is 4.5. The pOH of an aqueous buffer solution of HA in which 50% of the acid is ionized is

In a saturated solution of the sparingly soluble strong  electrolyte AgIO₃ (molecular mass = 283) the equilibrium which sets in is  If the solubility product constant K_sp of AgIO₃ at a given temperature is 1.0 × 10^–8, what is the mass of AgIO₃ contained in 100 ml of its saturated saolution?

The equilibrium constants K_p1 and K_p2 for the reactions  respectively are in the ratio of 1 : 9. If the degree of dissociation of X and Z be equal then the ratio of  total pressures at these equilibria is   

For the following three reactions a, b and c, equilibrium constants are given:

(i) CO(g) + H₂O(g) CO₂ (g)+ H₂ (g); K₁

(ii) CH₄ (g) + H₂O(g) CO(g)+ 3H₂ (g); K₂

(iii) CH₄ (g) + 2H₂O(g) CO₂ (g)+ 4H₂ (g); K₃

Four species are listed below:

i.
ii. H₃O⁺
iii. 
iv. H_SO₃F

Which one of the following is the correct sequence of their acid strength?

The pK_a of a weak acid, HA, is 4.80. The pK_b of a weak base, BOH, is 4.78. The pH of an aqueous solution of the correspondng salt, BA, will be

Solid Ba(NO₃)₂ is gradually dissolved in a 1.0 × 10^{– 4} M Na₂CO₃ solution. At what  concentration of Ba²⁺ will a precipitate begin to form? (K_SP for for BaCO₃ = 5.1 × 10^–9)

Three reactions involving H₂PO₄^– are given below :

(i) H₃PO₄ + H₂O → H₃O⁺ + H₂PO₄^–
(ii) H₂PO₄–  + H₂O → HPO₄^2– + H₃O⁺
(iii) H₂PO₄^– + OH^– → H₃PO₄ + O^2–

In which of the above does H₂PO₄^– act as an acid ? 

In aqueous solution the ionization constants for carbonic acid are

K₁ = 4.2 × 10^–7 and K₂ = 4.8 × 10^–11.

Select the correct statement for a saturated 0.034 M solution of the carbonic acid.

Solubility product of silver bromide is 5.0 × 10^–13. The quantity of potassium bromide (molar mass taken as 120  g mol^–1) to be added to 1 litre of 0.05 M solution of silver nitrate to start the precipitation of AgBr is

At 25°C, the solubility product of Mg(OH)₂ is 1.0 × 10^–11. At which pH, will Mg²+ ions start precipitating in the form of Mg(OH)₂ from a solution of 0.001 M Mg²⁺ ions?

A vessel at 1000 K contains CO₂ with a pressure of 0.5 atm.

Some of the CO₂ is converted into CO on the addition of graphite. If the total pressure at equilibrium is 0.8 atm, the value of K is :

The equilibrium constant (K_c) for the reaction  N₂(g) + O₂(g) → 2NO(g) at temperature T is 4 × 10^–4. Thevalue of K_c for the reaction

  at the same temperature is:

The pH of a 0.1 molar solution of the acid HQ is 3. The value of the ionization constant, K_a of the acid is :

How many litres of water must be added to 1 litre an aqueous solution of HCl with a pH of 1 to create an aqueous solution with pH of 2 ?

For the reaction  if K_P = K_C (RT)^x where the symbols have usual meaning then the value of x is (assuming ideality):

The standard Gibbs energy change at 300 K for the reaction  At a given time, the composition of the reaction mixture is  The reaction proceeds in the : [R = 8.314 J/K/mol, e = 2.718]

The following reaction is performed at 298 K.

The standard free energy of formation of NO(g) is 86.6 kj/mol at 298 K. What is the standard free energy of formation of NO₂(g) at 298 K? (K_p = 1.6 × 10¹²)

The equilibrium constant at 298 K for a reaction A +B C+D is 100. If the initial concentration of all the four species were 1 M each, then equilibrium concentration of D (in mol L^–1) will be :