Monitoring reactions by pressure, titration and optical rotation

28 questions on Monitoring reactions by pressure, titration and optical rotation from the Chemical Kinetics chapter: 6 NEET level, 11 JEE Main, 11 JEE Advanced. Each one opens with its answer and solution.

• A gaseous reaction A(g) -> B(g) + C(g) is carried out in a rigid closed vessel starting with pure A at pressure P_0. What is the total pressure when A has been ... NEET level
• In following the acid-catalysed hydrolysis of an ester by titrating equal aliquots with standard NaOH, the titre at infinite time (V_infty) corresponds to NEET level
• For a first-order reaction followed polarimetrically, with observed rotations r_0, r_t and r_infty at time zero, t and infinity, the rate constant is NEET level
• During the acid-catalysed inversion of sucrose, the observed optical rotation of the solution changes from positive to negative because NEET level
• Which of the following gaseous reactions, carried out at constant volume and temperature, cannot be followed by measuring the total pressure? NEET level
• A first-order reaction A(g) -> 2B(g) starts with pure A at pressure P_0 in a rigid vessel. The total pressure after exactly one half-life is NEET level
• The first-order gas-phase reaction A(g) -> B(g) + C(g) is carried out at constant volume starting with pure A at 400 mmHg. The total pressure is 550 mmHg after ... JEE Main level
• Acid-catalysed hydrolysis of an ester is followed by titrating 5 mL aliquots with NaOH. The titres are 12.0 mL at t = 0, 18.0 mL at t = 30 min and 36.0 mL at in... JEE Main level
• In a polarimetric study of sucrose inversion the rotation is +40 deg at t = 0, +13 deg at t = 60 min and -14 deg at infinite time. Assuming first-order kinetics... JEE Main level
• Aliquots of decomposing H2O2 solution are titrated with acidified KMnO4; the titre is proportional to [H2O2]. The titre falls from 40.0 mL at t = 0 to 25.0 mL a... JEE Main level
• A first-order reaction A(g) -> 2B(g) starts with pure A at 100 kPa in a rigid vessel. After exactly three half-lives the total pressure (in kPa) is JEE Main level
• The first-order gaseous reaction A(g) -> B(g) + C(g) starts with pure A at 300 mmHg in a constant-volume vessel; the total pressure is 408 mmHg after 15 min. Us... JEE Main level
• The first-order reaction A(g) -> 2B(g) + C(g) (k=0.03 min^-1) starts with pure A at 200 mmHg in a rigid vessel. Find the total pressure in mmHg after 30 min, to... JEE Main level
• The inversion of sucrose is pseudo-first-order with k=5.0x10^-3 min^-1. The initial rotation is +68.0 deg and the final rotation is -20.0 deg. Calculate the obs... JEE Main level
• In an ester hydrolysis followed by titration, the NaOH volumes are 10.0 mL (t = 0), 26.0 mL (t = 45 min) and 50.0 mL (infinite time). Find the first-order rate ... JEE Main level
• For a first-order reaction A(g) -> B(g) + C(g) in a rigid vessel starting with pure A at P_0, which statements are correct? (P_t is the total pressure at time t... JEE Main level
• For the inversion of sucrose, C12H22O11 + H2O -> glucose + fructose, in dilute acid (specific rotations in a common unit: sucrose +66.5, glucose +52.7, fructose... JEE Main level
• The first-order gas-phase reaction A(g) -> 3B(g) is studied at constant volume and temperature. The total pressure is 150 mmHg after 10 min, and 240 mmHg after ... JEE Advanced level
• In a first-order ester hydrolysis followed by NaOH titration, the titre at infinite time is 40.0 mL. The titre is 24.0 mL at t = 10 min and 36.0 mL at t = 30 mi... JEE Advanced level
• Sucrose inversion is followed polarimetrically. The initial rotation is +10.0 deg, the rotation at complete inversion is -6.0 deg, and after 40 min it is +2.0 d... JEE Advanced level
• The first-order decomposition 2N2O5(g) -> 4NO2(g) + O2(g) starts with pure N2O5 at 200 mmHg in a rigid vessel (ignore dimerisation of NO2). The total pressure i... JEE Advanced level
• The second-order reaction 2A(g) -> 2B(g) + C(g) starts with pure A at 100 kPa in a rigid vessel, and the total pressure is 112.5 kPa after 200 s. Calculate the ... JEE Advanced level
• A 10.0 mL aliquot of an acid-catalysed ester hydrolysis mixture is titrated with 0.100 M NaOH. The titres are 19.6 mL (t = 0), 31.6 mL (25 min) and 39.6 mL (inf... JEE Advanced level
• A polarimetric study of sucrose inversion gives rotations +24.0 deg (t = 0), +12.0 deg (t = 15 min) and -8.0 deg (infinite time). Assuming first-order kinetics ... JEE Advanced level
• Equal 10.0 mL aliquots of decomposing H2O2 are titrated with 0.0200 M KMnO4 in acid, using 2MnO4^- + 5H2O2 + 6H+ -> 2Mn^2+ + 5O2 + 8H2O. The titre is 25.0 mL at... JEE Advanced level
• The first-order reaction A(g) -> 3B(g) starts with pure A at pressure P_0 in a rigid vessel at constant temperature. P_t is the total pressure. Which statements... JEE Advanced level
• An acid-catalysed ester hydrolysis is followed by titration. The titres are 10.0 mL at t = 0, 20.0 mL at t = 20 min and 30.0 mL at infinite time. Assuming first... JEE Advanced level
• In the inversion of sucrose the rotations are +30 deg at t = 0, +10 deg at t = 40 min and -10 deg at infinite time (first order, ln2=0.693). Which statements ar... JEE Advanced level