Which statement is true with regards to activation energy in a reaction? All reactions, both endo and exothermic require activation energy because bonds must be broken before new bonds can form.

Only endothermic reactions require activation energy because the products contain more energy than the reactants.

A catalyst lowers the activation energy for a chemical reaction.  

Explanation:

From the given choices, it is true that a catalyst lowers the activation energy for a chemical reaction.

The activation energy is the energy barrier that must be overcome before a chemical reaction can occur.

Some reactions have very high activation energy and would not occur without the introduction of a catalyst.

The catalyst brings the reactants into contact by removing the energy deficiency in the system.

c. because step up transformer steps up the input voltage i.e increases the input voltage  

the number of turns are greater on the secondary side of step up transformer  

transformer does not handle dc current

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