Question

True/ False

A. _____The emf of a voltaic cell can change with temperature.

B. _____A reaction with a negative value of S and a positive value of H at a given temperature is not spontaneous at that temperature.

C. _____The change in entropy is positive when a piece of table sugar dissolves in water.

D. _____A ligand is always a Lewis base.

E. _____A hydrogen fuel cell requires oxygen to operate.

F. _____When the temperature of a ferromagnetic material is raised to a high enough level, it becomes diamagnetic.

G. _____The solubility of barium hydroxide is higher in pure water than it is in 1.0M hydrochloric acid.

H. _____In any reversible process, the entropy remains constant.

I. _____If two molecules are isomers of each other, they always have the same chemical formula.

J. _____A square planar molecule can never be chiral.

K. _____The entropy of an element in its standard state is zero.

L. _____At equilibrium, the change in free energy for a given reaction is zero.

Answer 1

A) true --- [Nernst equation supports the statement , increase in temperature decreases cell potential

B) True -- [for a system to be spontaneous , entropy must be +ve and enthalpy -ve]

C) True - [ dissolution of sugar is spontaneous, dissolution of sugar solid in water is increase in temperature]

D) True -[ ligands receives electron pair from central atom always in a complex compound]

E) True -[ electrochemical reaction between hydrogen and oxygen generate electricity in hydrogen fuel cell]

F) False -- [ on heating ferromagnetic material they do become paramagnetic--- CURIE temperature explains this magnetic behaviour of magnetic materials, paramagnetic materials on heating above curie temeprature may become diamagnetic]]

G) False -- [ barium hydroxide is more soluble in acid forming barium chloride]

H) True -- [second law of thermodynamics supports this statement, irreversible process shows increment in entropy.]

I) True -- [ isomers are of same chemical formula and different arrangements of groups]

J) True - [ square planar complex do not exhibit optical isomeism, tetrahedral complexes exhibits optical isomerism]

K)False - [ the entropy can never be zero , entropy will be zero only when the pure crystal that exists at absolute temperature]

absolute temperature is 0k

L)True - [ yes , at equilibriun the free energy change is zero]