Question

Which of the following pairs of processes is certain to occur in a spontaneous chemical reaction?

A. Exothermic and increasing disorder  
B. Exothermic and decreasing disorder
C. Endothermic and increasing disorder
D. Endothermic and decreasing disorder
Answer :   Exothermic and increasing disorder
Solution :
Measure of disorder of a system is nothing but entropy. For a spontaneous reaction, $$\Delta G < 0.$$   As per Gibbs Helmholtz equation, $$\Delta G = \Delta H - T\Delta S$$
Thus $$\Delta G$$  is $$ - ve$$  only
when $$\Delta H = - ve$$   (exothermic)
and $$\Delta S = + ve$$   (increasing disorder)

Releted MCQ Question on
Physical Chemistry >> Chemical Thermodynamics

Releted Question 1

The difference between heats of reaction at constant pressure and constant volume for the reaction : $$2{C_6}{H_6}\left( l \right) + 15{O_{2\left( g \right)}} \to $$     $$12C{O_2}\left( g \right) + 6{H_2}O\left( l \right)$$     at $${25^ \circ }C$$  in $$kJ$$ is

A. $$-$$ 7.43
B. $$+$$ 3.72
C. $$-$$ 3.72
D. $$+$$ 7.43
View Answer
Releted Question 2

For which change $$\Delta H \ne \Delta E\,:$$

A. $${H_{2\left( g \right)}} + {I_{2\left( g \right)}} \to 2HI\left( g \right)$$
B. $$HC{\text{l}} + NaOH \to NaC{\text{l}}$$
C. $${C_{\left( s \right)}} + {O_{{2_{\left( g \right)}}}} \to C{o_{{2_{\left( g \right)}}}}$$
D. $${N_2}\left( g \right) + 3{H_2}\left( g \right) \to 2N{H_3}\left( g \right)$$
View Answer
Releted Question 3

$${\text{The}}\,\Delta H_f^0\,{\text{for}}\,C{O_2}\left( g \right),\,CO\left( g \right)\,$$     and $${H_2}O\left( g \right)$$   are $$-393.5,$$  $$-110.5$$  and $$ - 241.8\,kJ\,mo{l^{ - 1}}$$    respectively. The standard enthalpy change ( in $$kJ$$ ) for the reaction $$C{O_2}\left( g \right) + {H_2}\left( g \right) \to CO\left( g \right) + {H_2}O\left( g \right)\,{\text{is}}$$

A. 524.1
B. 41.2
C. -262.5
D. -41.2
View Answer
Releted Question 4

In thermodynamics, a process is called reversible when

A. surroundings and system change into each other.
B. there is no boundary between system and surroundings.
C. the surroundings are always in equilibrium with the system.
D. the system changes into the surroundings spontaneously.
View Answer

Practice More Releted MCQ Question on
Chemical Thermodynamics

Practice More MCQ Question on Chemistry Section

Physical ChemistrySome Basic Concepts in ChemistryStoichiometryStates of Matter Solid, Liquid and GasAtomic StructureChemical ThermodynamicsSolutionsSolid StateSurface ChemistryChemical EquilibriumIonic EquilibriumChemical KineticsRedox ReactionElectrochemistryNuclear Chemistry
Inorganic ChemistryChemical Bonding and Molecular StructureOres and MetallurgyClassification of Elements and Periodicity in PropertiesHydrogenS - Block ElementsP - Block ElementsD and F Block ElementsCo - ordination CompoundsQualitative AnalysisPreparation and Properties of CompoundsEnvironmental Chemistry
Organic ChemistryGeneral Organic ChemistryIsomerismPurification and Characterisation of Organic CompoundsHydrocarbons (Alkane, Alkene and Alkyne)Aromatic hydrocarbonElectrophilic Aromatic Substitution (Haloalkanes and Haloarenes)Alkyl and Aryl HalideReactions on BenzeneAlcohol, Phenol and EtherAldehyde and KetoneCarboxylic AcidOrganic Compounds Containing NitrogenName ReactionsPolymersBiomoleculesChemistry in Everyday LifePractical Organic Chemistry