Thermal decomposition of ammonium dichromate gives

• N₂, H₂O and Cr₂O₃

• N₂, NH₃ and CrO

• (NH₄)₂CrO₄ and H₂O

• N₂, H₂O and CrO₃

92.

The enthalpy change for a reaction at equilibrium is -20.5 kJ mol^-1. Then the entropy change for this equilibrium at 410 K is

• +50 JK^-1mol^-1

• +55 JK^-1mol^-1

• +75 JK^-1mol^-1

• -50 JK^-1mol^-1

The enthalpy of combustion of glucose (mol.wt.: 180 g mol^-1) is -2840 kJ mol^-1. Then the amount of heat evolved when 0.9 g ofglucose is burnt, will be

• 14.2 kJ

• 142 kJ

• 28.4 kJ

• 1420 kJ

The entropy of vaporisation of a liquid is 58 JK^-1 mol^-1. If 100 g of its vapour condenses at its boiling point of 123° C, the value of entropy change for the process is

• -100 JK^-1

• 100 JK^-1

• -123 JK^-1

• 123 JK^-1

At constant external pressure of one atmosphere, 4 moles of a metallic oxide MO₂ undergoes complete decomposition at 227°C in an open vessel according to the equation

2MO₂ (s) → 2MO (s) + O₂ (g)

The work done by the system in kJ is (R = 8.3 kJ mol^-1)

• -16.6

• -24.9

• -33.2

• -4.15

A certain reaction has a $∆$H of 12 kJ and a $∆$S of 40 JK^-1. The temperature above which the reaction becomes spontaneous is

• 27°C

• 27 K

• 300°C

• 30 K

Mathematical equation of first law of thermodynamics for isochoric process is

• ΔU = q_v

• -ΔU = q_v

• q= -W

• ΔU = W

The criterion for a spontaneous process is

• ΔG >0 

• ΔG < 0

• ΔG = 0

• ΔS_total < 0

Choose the reaction in which $∆$H is not equal to $∆$U

• C(graphite) + O₂(g) → CO₂(g)

• C₂H₄(g) + H₂(g) → C₂H₆(g)

• 2C(graphite) + H₂(g) → C₂H₂(g)

• H₂(g) + I₂(g) → 2HI(g)

The standard enthalpies of combustion of C₆H₆ (l), C_(graphite) and H₂ (g) are respectively -3270 kJ mol^-1, -394 kJ mol^-1 and -286 kJ mol^-1. What is the standard enthalpy of formation of C₆H₆ (l) in kJ mol^-1?

• -48

• +48

• -480

• +480