Tiêu đề Chemical Kinetics.pdf ✅

JEE Q7 For a reaction of order n, the integrated form of the rate equation is (n – 1) Kt = (C ) – (C) where C and C are the values of the reactant concentration at the start and after time ‘t’. What is the relationship between t and t , where t is the time required for C to become C /4 (A) t = t . [2 +1] (B) t = t . [2 –1] (C) t = t . [2 –1] (D) t = t . [2 +1] Q8 For the first-order gaseous reaction A(g) 2B(g), A(g) C(g), the initial pressure in a container of fixed volume, V litre, is 1 atm. Pressure of the system is 1.4 atm at t = 10 minute and the pressure is 1.5 atm after a very long time. The only correct information about the reaction is (ln 2 = 0.7, ln 10 = 2.3) (A) 2K = K = 0.08 min (B) K = K = 0.08 min (C) K = 2K = 0.08 min (D) K = K = 0.16 min Q9 For certain reaction it is observed that ln k = α + β ln T – , where K is the rate constant, T is the temperature (Klevin) and α, β and γ are constants. What is the Arrhenius activation energy? (A) βRT + γR (B) γR (C) β + γR (D) βRT – γR Q10 The order of reaction A →Products, may be given by which of the following expression(s)? Where are of reaction [A] = conc. At t [A] conc. At t . (A) (B) (C) (D) Q11 For a reaction involving a single reactant and order than one, which of the following statement(s) is/are true? (C = concentration of reaction at time, t) (A) If f is the fraction of the reactant concentration consumed over time interval ‘t’, then log is linearly related to (log C), when f << 1. (B) A plot of C vs t is linear with slope proportional to (n –1) (C) If t and t are the time intervals for 50% and 75% consumption of the reactant, then t : t = 2 + 1 (D) A plot of log C vs log t is linear with slope= 1. Q12 α-maltose (C H O ) can be hydrolysed to glucose (C H O ) as follows. C H O (aq) + H O(l) → 2C H O (aq) On the basis of following data, identify the correct statement(s) related with the reaction. Δ = –2238 kJ/mol, Δ = – 1263 kJ/mol, Δ = – 285 kJ/mol Time (minute) 0 50 100 Conc. of α-maltose(M) 0.4 0.1 0.025 (A) The hydrolysis of α -maltose is an exothermic process. (B) Heat liberated in the combustion of 1.0 mole of α-maltose must be greater than the heat liberated in combustion of 2.0 moles of glucose. (C) On increasing the temperature, the extent of hydrolysis of α-maltose will decrease. 0 1–n 1 – n 0 3/4 1/2 3/4 0 3/4 1/2 n–1 3/4 1/2 n–1 3/4 1/2 n+1 3/4 1/2 n+1 → K1 → K2 1 2 –1 1 2 –1 1 2 –1 1 2 –1 γ T 1 1 2 2 ln −ln r2 r1 ln −ln [A]2 [A]1 ln −ln [ ] A0 2 [ ] A0 1 ln −ln [ ] t1/2 2 [ ] t1/2 1 1 + ln −ln [ ] A0 2 [ ] A0 1 ln −ln [ ] t1/2 2 [ ] t1/2 1 ln (r/K) ln [A] ( )f t (n –1) 1/2 3/4 3/4 1/2 n–1 12 22 11 6 12 6 12 22 11 2 6 12 6 f HoC (aq) 12H22O11 f HoC (aq) 6H12O6 f HoH O(l) 2
JEE (D) The hydrolysis of a-maltose follows first- order kinetics. Q13 For the parallel reactions A B and A C, the initial concentration of ‘A’ is and initially ‘B’ and ‘C’ are absent. Concentrations of A, B and C at any time ‘t’ is C , C and Cc, respectively. The correct relation(s) is/are (A) C +C +C = (B) (C) (D) Q14 In a study of effect of temperature on reaction rate, the value of . is found to be K . Identify the correct statement(s). (A) The activation energy for the reaction at 250 K is 10 kcal/mol. (B) The activation energy for the reaction at 2000 K is 1.25 kcal/mol. (C) The rate of increase of rate constant with the increase in temperature is higher at lower temperature than at higher temperature. (D) The value of is 0.625 at 1000 Q15 For a chemical reaction A + B → Products, the order is one with respect to each A and B. The sum of x and y from the following data is as follows. Q16 For the reaction 2NO(g) + H (g) → N O(g) + H O(g), the value of – was found to be 1.5 Pa s for a pressure of 372 Pa for NO and 0.25 Pa s for a pressure of 152 Pa for NO, the pressure of H being constant. If pressure of NO was kept constant, the value of – was found to be 1.60 Pa s for a pressure of 289 Pa for H and 0.79 Pa s for a pressure of 147 Pa for H . If the order of reaction with respect to NO and H are a and b, respectively, then the value of (a + b) is: (Nearest Integer) Q17 A drug is known to be ineffective after it has decomposed 30%. The original concentration of a sample was 500 units/ml. When analysed 20 months later, the concentration was found to be 420 units/ml. Assuming that the decomposition is first order, what will be the expiration time (in month) of the drug? (ln 2 = 0.7, In 5 = 1.6, ln 7 = 1.9, ln 3= 1.1) (Nearest Integer) Q18 For a reaction 2A + B→ C + D, the following data is collected by experiments. The value of (a + b + c + d) is Q19 The rate of decomposition for CH NO and C H NO can be given in terms of rate constant (in s ) K and K , respectively. The energy of activation for these reactions is 152.30 and 157.7 kJ/mol and the frequency factors arc 10 and 10 s , respectively. The temperature (in °C) at which rate constant will be same for both decomposition reactions, is (R = 8.3 J/K-mol, ln 10 = 2.3) → K1 → K2 CA0 A B A B C CA0 + + = 0 dCA dt dCB dt dCC dt = CB CC K1 K2 = CB CA0 −CA K1 K1+K2 ⋅ 1 K dK dT 1.25×106 T 3 –1 d(lnK) dT 2 2 2 dP dt –1 –1 2 dP dt –1 2 –1 2 2 3 2 2 5 2 –1 1 2 13 14 –1
JEE Answer Key Q 1 ( A ) Q 2 ( B ) Q 3 ( B ) Q 4 ( D ) Q 5 ( D ) Q 6 ( B ) Q 7 ( A ) Q 8 ( B ) Q 9 ( A ) Q10 ( A, C, D ) Q11 ( A, C ) Q12 ( A, C, D ) Q13 ( A, B, C, D ) Q14 ( A, B, C ) Q15 (01.00) Q16 (03.00) Q17 (41.00) Q18 (260.00) Q19 (282.00)