30. Which of the following statements is /are true? A. The following reaction is

Question

30. Which of the following statements is /are true?

A. The following reaction is identified as exothermic and the entropy is decreasing with reaction CH4 (g) + 2O2 (g) = CO2 (g) + 2H2O (l) H0 = - 890.4 kJ

B. A mercury cell formerly used to power heart pacemakers has the following reaction: The process of the reduction of mercury and the oxidation of zinc in this reaction is a spontaneous. Zn (s) + HgO (s)= ZnO (s) + Hg (l) E= 1.35 V

C. Galvanic cell: (also called a voltaic cell) uses a spontaneous chemical reaction to generate electricity.

D. Batteries and fuel cells are galvanic cells that consume their reactants to generate electricity. A battery has a static compartment filled with reactants. In a fuel cell, fresh reactants flow past the electrodes and products are continuously flushed from the cell.

E. All of the above statements are true.

Explanation / Answer

Answer is E.

All the above statements are correct.

A) In the reactionCH4 (g) + 2O2 (g) = CO2 (g) + 2H2O (l) H0 = - 890.4 kJ.

The negative value means the reaction is exothermic. Here gaseous reactants changes to gas and liquid products ,this shows during reaction an ordered state is attained that is entropy decreases.

Regarding B,C,D all the facts are right.

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