CHEMICAL EQUILIBRIUM QUIZ-2

CHEMISTRY CHEMICAL EQUILBRIUM QUIZ-2

Dear Readers,

The one subject in NEET which is candidates who can easily attain good marks is Chemistry. That's the reason, often, one doesn’t pay notice and choose to compromise it. But if one wants to rank above others, the tip is to be thorough with NEET chemistry concepts. The understanding of reactions and definite basic understanding is what requires major attention in Chemistry but once done it only gets simpler from there. The main focus on the to-do list should be on getting a hang of the NCERT syllabus of NEET chemistry.

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Q1. For the reversible reaction, N₂(g)+3H₂(g)⇌2NH₃(g) at 500℃, the value of K_p is 1.44×10^(-5). When partial pressure is measured in atmospheres.
The corresponding value of K_c with concentration in mol L^(-1) is

•  1.44×10^-5⁄(0.082×773)^-3
•  1.44×10^-5⁄(0.082×500)^-2
•  1.44×10^-5⁄(0.314×773)²
•  1.44×10^-5⁄(0.082×773)^-2

Solution
(d) For the reversible reaction, N₂ (g)+3H₂(g)⇌2NH₃(g) ∆n_g=2-(1+3) =2-4=-2 R=0.0821 L atm K^(-1) mol^(-1) T=500+273=773 K K_p=K_c(RT)^{(∆n_g) K_p=K_c×(RT)(-2) or K_c=K_p/(RT)(-2) =(1.44×10(-5))/(0.082×773)(-2) or (1.44×10(-5))⁄(0.082×773)(-2)}

Q2.Le-Chatelier principle is applicable only to a

•  System in equilibrium
•  System not in equilibrium
•  Homogeneous reaction
•  Heterogeneous reaction

Solution
(a)

Q3.  The expression for the solubility product of Ag₂CO₃ will be

•  K_sp s²
•  K_sp 4s³
•  K_sp 27s⁴
•  K_sp s

Solution
(b) Ag₂CO₃(s)⇌2Ag⁺+CO₃^{^}(2-) s 2s s K_sp=[Ag⁺ ]² [CO₃^(2-)]=(2s)².s ∴ K_sp=4s³

Q4. The combination of H⁺ and OH^- to produce H₂O is called:

•  Hydrolysis
•  Neutralization
•  Dehydration
•  Dehydrohalogenation

Solution
(b) H⁺+OH^-⟶H₂O;∆H=13.7 kcal is neutralization process.

Q5.The pK_a of HCN is 9.30. The pH of a solution prepared by mixing 2.5 moles of KCN and 2.5 moles of KCN and 2.5 moles of HCN in water and making up the total volume of 500 mL, is

•  9.30
•  7.30
•  10.30
•  8.30

Solution
 a) pH=pK_a+log⁡([KCN]/[HCN]) =9.3+log⁡(2.5/2.5)=9.30

Q6.If in the reaction N₂O₄⇌2NO₂,α is degree of dissociation of N₂O₄, then the number of molecules at equilibrium will be:

•  3
•  1
•  (1-α)²
•  (1+α)

Solution
d) N₂O₄⇌2NO₂ 1 0 (1-α) 2α ∴ Total mole at equilibrium =1-α+2α=1+ α

Q7.A gaseous phase reaction is allowed to attain equilibrium as A(g)⇌B(g)+C (g) at constant pressure P. The partial pressure of A at equilibrium is P/2. The value of equilibrium constant K_P is∶

•  P/2
•  P/4
•  P/6
•  P/8

Solution
d) A ⇌ B+C P_A^'=(a-x)P/((a+x))=P/2 ∴ x=a/3 ∴ K_p=(x.x)/(a-x) x [p/(a+x)]¹ =(a/3 ×a /3 × P)/(a²-a²/9) = P/8

Q8.5 moles of SO₂ and 5 moles of O₂ are allowed to react. At equilibrium, it was found that 60% of SO₂ is used up. If the partial
pressure of the equilibrium mixture is one atmosphere, the partial pressure of O₂ is

•  0.82 atm
•  0.52 atm
•  0.21 atm
•  0.41 atm

Solution
d) 2SO₂ (g) + O₂(g) ⇌ 2SO₃ (g) Initial 5 5 0 At equilibrium (5-3) (5-1.5) 3 =2 =3.5 ∴pO₂=(3.5×1)/8.5=0.41atm

Q9.The value of K_p for the following reaction 2H₂S(g)⇌2H₂(g)+S₂(g),is 1.2×10^(-2) at 106.5℃. The value of K_c for this reaction is

•  =1.2×10^(-2)
•   <1.2×10^(-2)
•  >1.2×10^(-2)
•  None of these

Solution
(b) K_p=K_c(RT)^{(∆n_g )} Here, ∆ng=1 Thus, K_{c will be less than Kp}

Q10. If NaOH is added to a solution of acetic acid:

•  H⁺ ions increases
•   pH decreases
•   [C₂H₃O₂]^- increases
•   [HC₂H₃O₂] increases

Solution
c) Dissociation of acetic acid increases as, CH₃COOH+NaOH⟶CH₃COONa+H₂O Concentration of mixture