'The free energy change due to a reaction is zero when-

1. The reactants are initially mixed.

2.  A catalyst is added

3. The system is at equilibrium

4. The reactants are completely consumed

An ideal gas expands at a constant external pressure of 2.0 atmosphere by 20 litre and absorbs 10kJ of heat from surrounding. What is the change in internal energy of the system:-

(1) 4052 J

(2) 5948 J

(3) 14052 J

(4) 9940 J

The temperature of an ideal gas expansion increases in an:-

(1) Adiabatic expansion

(2) Isothermal expansion

(3) Adiabatic compression

(4) Isothermal compression

36 ml of pure water takes 100 sec to evaporate from a vessel and heater connected to an electric source which delivers 806 watt. The $∆{\mathrm{H}}_{\mathrm{vaporisation}}$ of H₂O is:-

(1) 40.3 kJ/mol

(2) 43.2 kJ/mol

(3) 4.03 kJ/mol

(4) None of these

5 moles of an ideal gas expands isothermally and irreversibly from a pressure of 10 atm to 1 atm against a constant external pressure of 1 atm. find the W_irr at 300 K:-

1. -15.921 kJ

2. -11.224 kJ

3. -110.83 kJ

4. None of these

In the reaction at 300 K

H₂(g) + Cl₂(g)$\to$2HCl(g)       $∆\mathrm{H}°$= -185 kJ

if 2 mol of H₂ completely react with 2 mole of Cl₂ to form HCl. What is $∆\mathrm{U}°$ for this reaction?

(1) 0

(2) -185 kJ

(3) -370 kJ

(4) None of these

Which of the following reactions has/have a positive \(\Delta S\) (entropy change)?

(i) Ag⁺ (aq) + Cl^-(aq) $\to$AgCl(s)

(ii) NH₄Cl(g) $\to$NH₃(g) + HCl(g)

(iii) 2NH₃(g)$\to$N₂(g) + 3H₂(g)

1. (i) & (ii)

2. (iii)

3. (ii) & (iii)

4. (ii)

When two moles of an ideal gas (Cp, m=$\frac{5}{2}$R) heated from 300 K to 600 K at constant pressure the change in entropy of gas ($∆\mathrm{S}$) is:-

(1) $\frac{3}{2}$Rln2

(2) -$\frac{3}{2}$Rln2

(3) 7R ln 2

(4) 5 Rln2

The free energy change $∆\mathrm{G}$=0 when:-

(1) The system is at equilibrium

(2) Catalyst is added

(3) Reactants are initially mixed throughly

(4) The reactants are completely consumed

For isothermal expanison in case of an ideal gas:-

(1) $∆$G=$∆$S

(2) $∆$G=$∆$H

(3) $∆$G=-T$∆$S

(4) None of these