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Thermodynamics · Question 1

JEE Main 2026 (Online) 8th April Evening ShiftNumericalEasy📈 Topic in 26% papers+4
1

Consider the reaction 2H2S(g) + 3O2(g) 2H2O(l) + 2SO2(g) The magnitude of enthalpy change for the reaction in kJ mol-1 is . (Nearest integer) Given : f H (H2S) = -20.1 kJ mol-1 f H (H2O) = -286.0 kJ mol-1 f H (SO2) = -297.0 kJ mol-1

Answer

1126

Solution

r H = f H (products) - f H (reactants) ( f H of O2 = 0)

= [2(-286.0) + 2(-297.0)] - [2(-20.1) + 0]

= -1166.0 + 40.2

= -1125.8 kJ mol-1

∴ Magnitude ≈ 1126

Answer: 1126

JEE Main 2026 (Online) 8th April Evening Shift

Keep practising — Thermodynamics

2

Arrange the following isothermal processes in order of the magnitude of the work (p − V) involved between states 1 and 2. Choose the correct option.

  1. |wB| > |wA| > |wC| > |wD|
  2. |wC| > |wD| > |wA| > |wB|
  3. |wC| > |wD| > |wB| > |wA|
  4. |wB| > |wA| > |wD| > |wC|
JEE Main 2026 (Online) 6th April Morning Shift
3

Consider the reaction X Y at 300 K. If H and K are 28.40 kJ mol-1 and 1.8 10-7 at the same temperature, then the magnitude of S for the reaction in J K-1 mol-1 is . (Nearest integer) (Given : R = 8.3 J K-1 mol-1, ln 10 = 2.3, log 3 = 0.48, log 2 = 0.30)

JEE Main 2026 (Online) 6th April Morning Shift
4

Match List - I with List - II. Given V1 and V2 are initial and final volumes respectively. Choose the correct answer from the options given below :

  1. A-II, B-III, C-I, D-IV
  2. A-II, B-I, C-IV, D-III
  3. A-II, B-I, C-III, D-IV
  4. A-I, B-II, C-III, D-IV
JEE Main 2026 (Online) 6th April Evening Shift
5

Consider the following data for the reaction X2(g) + Y2(g) 2XY(g) at 600 K. The rG (in kJ mol-1) for the reaction is : array|c|c|c| Compound & fH 600 K ( kJ mol-1) & S 600 K ( J mol-1 K-1) \ XY(g) & 42 & 200 \ X2(g) & 8 & 140 \ Y2(g) & 80 & 250 \ array

  1. −21000
  2. −10
  3. −1000
  4. −9.012
JEE Main 2026 (Online) 5th April Evening Shift
6

The correct order of molar heat capacities measured at 298 K and 1 bar is :

  1. Copper(s) > Bromine(l) > Helium(g)
  2. Bromine(l) > Copper(s) > Helium(g)
  3. Helium(g) > Bromine(l) > Copper(s)
  4. Helium(g) > Bromine(l) = Copper(s)
JEE Main 2026 (Online) 5th April Evening Shift
7

Given below are two statements : In the light of the above statements, choose the correct answer from the options given below

  1. Both Statement I and Statement II are true
  2. Both Statement I and Statement II are false
  3. Statement I is true but Statement II is false
  4. Statement I is false but Statement II is true
JEE Main 2026 (Online) 4th April Morning Shift
8

If 3.365 g of ethanol (l) is burnt completely in a bomb calorimeter at 298.15 K, the heat produced is 99.472 kJ. The | Hf | of ethanol at 298.15 K is 102 kJ mol-1. (Nearest integer) Given: Standard enthalpy for combustion of graphite = −393.5 kJ mol-1 Standard enthalpy of formation of water (l) = −285.8 kJ mol-1 Molar mass in g mol-1 of C, H, O are 12, 1 and 16 respectively

JEE Main 2026 (Online) 4th April Evening Shift
9

Consider the following data. (i) 2Al(s) + 6HCl(aq) Al2Cl6(aq) + 3H2(g) + 1200 kJ/mol (ii) H2(g) + Cl2(g) 2HCl(g) + 164 kJ/mol (iii) HCl(g) + aq HCl(aq) + 83 kJ/mol (iv) Al2Cl6(s) + aq Al2Cl6(aq) + 663 kJ/mol The enthalpy of formation of anhydrous solid Al2Cl6 is :

  1. -648 kJ mol-1
  2. -1350 kJ mol-1
  3. -2002 kJ mol-1
  4. -1527 kJ mol-1
JEE Main 2026 (Online) 2nd April Morning Shift
10

At the transition temperature T, A B and G = 105 - 35 T where A and B are two states of substance X. The transition temperature in °C when pressure is 1 atm is . (Nearest integer)

JEE Main 2026 (Online) 2nd April Morning Shift
11

Gas 'A' undergoes change from state 'X' to state 'Y'. In this process, the heat absorbed and work done by the gas is 10 J and 18 J respectively. Now gas is brought back to state 'X' by another process during which 6 J of heat is evolved. In the reverse process of 'Y' to 'X',

  1. 18 J of the work is done by the gas 'A'.
  2. 2 J of the work is done by the gas 'A'.
  3. 12 J of the work is done on the gas 'A' by the surrounding.
  4. 14 J of the work is done on the gas 'A' by the surrounding.
JEE Main 2026 (Online) 2nd April Evening Shift

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