These are Assertion-Reason type questions.Question contains two statements:Statement-1 (Assertion) and Statement-2 (Reason). Answer these question from the following four options.

Statement 1 :Internal energy is an extensive property.
Statement 2 :Internal energy depends upon the amount of the system.

Statement-1 is True, Statement-2 is True, Statement-2 is a correct explanation for Statement-1
Statement-1 is True, Statement-2 is True Statement-2 is NOT a correct explanation for Statement-1
Statement - 1 is True, Statement-2 is False
Statement -1 is False, Statement-2 is True

Solution

The properties whose magnitude depends upon the quantity of matter present in the system are called extensive properties eg, internal energy.

The standard enthalpy of formation (Δ_fHº) at 298 K form ethane,CH₄ (g) is –74.8kJ mol^-1. The additional information required to determine the average energy for C – H bond formation would be

the first four ionization energies of carbon and electron gain enthalpy of hydrogen
the dissociation energy of hydrogen molecule, H₂
the dissociation energy of H₂ and enthalpy of sublimation of carbon
latent heat of vapourization of methane

Solution

The standard enthalpy of formation of CH4 is given by the equation
C(s) + 2H₂(g) ⟶ CH₄(g)
Hence, dissociation energy of hydrogen and enthalpy of sublimation of carbon is required.

If the bond dissociation energies of XY, X₂ and Y₂ (all diatomic molecules) are in the ratio of 1 : 1 : 0.5 and Δ_fH for the formation of XY is – 200 kJ mole–1. The bond dissociation energy of X₂ will be

400 kJ mol^-1
300 kJ mol^-1
200 kJ mol^-1
800 kJ mol^-1

Solution

In an irreversible process taking place at constant T and P and in which only pressure-volume work is being done, the change in Gibbs free energy (dG) and change in entropy (dS), satisfy the criteria

(dS)_{V, E} > 0, (dG)_{T, P} < 0
(dS)_{V, E} = 0, (dG)_{T, P} = 0
(dS)_{V, E} = 0, (dG)_{T, P} > 0
(dS)_{V, E} < 0, (dG)_{T, P} < 0

Solution

For spontaneous reaction, dS > 0 and dG should be negative i.e., < 0.

The internal energy change when a system goes from state A to B is 40 kJ/mole. If the system goes from A to B by a reversible path and returns to state A by an irreversible path what would be the net change in internal energy ?

> 40 kJ
< 40 kJ
Zero
40 k

Solution

For the reactions,
C + O₂ ⟶ CO₂ ; ΔH= –393 J
2Zn + O₂ ⟶ 2ZnO ; ΔH= –412J

carbon can oxidise Zn
oxidation of carbon is not feasible
oxidation of Zn is not feasible
Zn can reduce carbon dioxide

Solution

For the reaction A ⟶ B; ΔH= + 24 kJ/mol and B ⟶ C;ΔH= – 18 kJ/mol, the decreasing order of enthalpy of A, B and C follows the order

A, B, C
B, C, A
C, B, A
C, A, B

Solution

Solution

Hydrogen has an ionisation energy of 1311 kJ mol^-1 and for chlorine it is 1256 kJ mol^-1. Hydrogen forms H⁺ (aq) ions but chlorine does not form Cl⁺ (aq) ions because

H⁺ has lower hydration enthalpy
Cl⁺ has lower hydration enthalpy
Cl has high electron affinity
Cl has high electronegativity

Solution

Hydration energy of Cl⁺ is very less than H⁺ hence it doesn’t form Cl⁺ (aq) ion.

Equal volumes of molar hydrochloric acid and sulphuric acid are neutralized by dil. NaOH solution and x kcal and y kcal of heat are liberated respectively.Which of the following is true?

x = y
x = ¹/₂ y
x = 2y
None of these

Solution

1 M H₂SO₄= 2g eq. of H₂SO₄
Hence y= 2x or x = ¹/₂ y

UnAttempted

0

Attempted

0

Correct

0

Wrong

0

Complete