PYQSide ExamsMy practice

Thermodynamics · Question 39

AIPMT 2011 (Prelims)MCQEasy📈 Topic in 12% papers+4−1
1

Enthalpy change for the reaction, 4H(g) 2H2(g) is -869.6 kJ The dissociation energy of H-H bond is

  1. -434.8 kJ
  2. -869.6 kJ
  3. +434.8 kJ
  4. +217.4 kJ

Answer

(3) +434.8 kJ

Solution

Formation of 2 mol H–H bonds: 4H(g) 2H2(g); H = -869.6 kJ

reverse (dissociation): 2H2(g) 4H(g); H = +869.6 kJ

for 1 mol: H2(g) 2H(g); H = +869.62 = +434.8 kJ

Bond dissociation energy is always positive (energy is absorbed to break a bond).

Answer: (3)

AIPMT 2011 (Prelims)

Keep practising — Thermodynamics

2

Which of the following is correct option for free expansion of an ideal gas under adiabatic condition ?

  1. q = 0, T 0, w = 0
  2. q 0, T = 0, w = 0
  3. q = 0, T = 0, w = 0
  4. q = 0, T < 0, w 0
AIPMT 2011 (Prelims)
3

Match List I (Equations) with List II (Type of processes) and select the correct option.

  1. A - (i), B - (ii), C - (iii), D - (iv)
  2. A - (iii), B - (iv), C - (ii), D - (i)
  3. A - (iv), B - (i), C - (ii), D - (iii)
  4. A - (ii), B - (i), C - (iv), D - (iii)
AIPMT 2010 (Mains)
4

Three moles of an ideal gas expanded spontaneously into vacuum. The work done will be

  1. infinite
  2. 3 Joules
  3. 9 Joules
  4. zero
AIPMT 2010 (Mains)
5

For vaporization of water at 1 atmospheric pressure, the values of H and S are 40.63 kJ mol-1 and 108.8 J K-1 mol-1, respectively. The temperature when Gibbs energy change ( G) for this transformation will be zero, is

  1. 273.4 K
  2. 393.4 K
  3. 373.4 K
  4. 293.4 K
AIPMT 2010 (Mains)
6

The following two reactions are known Fe2O3(s) + 3CO(g) 2Fe(s) + 3CO2(g); H = -26.8 kJ FeO(s) + CO(g) Fe(s) + CO2(g); H = -16.5 kJ The value of H for the following reaction Fe2O3(s) + CO(g) 2FeO(s) + CO2(g) is

  1. +10.3 kJ
  2. -43.3 kJ
  3. -10.3 kJ
  4. +6.2 kJ
AIPMT 2010 (Mains)
7

Standard entropies of X2, Y2 and XY3 are 60, 40 and 50 J K-1 mol-1 respectively. For the reaction 12X2 + 32Y2 XY3, H = -30 kJ, to be at equilibrium, the temperature should be

  1. 750 K
  2. 1000 K
  3. 1250 K
  4. 500 K
AIPMT 2010 (Prelims)
8

The values of and for the reaction, C(graphite) + CO2(g) 2CO(g) are 170 kJ and 170 J K-1, respectively. This reaction will be spontaneous at

  1. 910 K
  2. 1110 K
  3. 510 K
  4. 710 K
AIPMT 2009
9

From the following bond energies : H – H bond energy : 431.37 kJ mol-1 C = C bond energy : 606.10 kJ mol-1 C – C bond energy : 336.49 kJ mol-1 C – H bond energy : 410.50 kJ mol-1 Enthalpy for the reaction, [figure] will be

  1. -243.6 kJ mol-1
  2. -120.0 kJ mol-1
  3. 553.0 kJ mol-1
  4. 1523.6 kJ mol-1
AIPMT 2009
10

Bond dissociation enthalpies of H2, Cl2 and HCl are 434, 242 and 431 kJ mol-1 respectively. Enthalpy of formation of HCl is

  1. -93 kJ mol-1
  2. 245 kJ mol-1
  3. 93 kJ mol-1
  4. -245 kJ mol-1
AIPMT 2008
11

For the gas phase reaction, PCl5(g) PCl3(g) + Cl2(g) which of the following conditions are correct?

  1. < 0 and < 0
  2. > 0 and < 0
  3. = 0 and < 0
  4. > 0 and > 0
AIPMT 2008

All Thermodynamics PYQs →

PDFDownload Thermodynamics PYQs as PDF Free, with answer key and a QR code to every solution — print it or study offline⬇
All NEET Chemistry chapters