how a catalyst can provide a new route in forming the product?
a catalyst does not provide a new route. it just lowers something called the energy of activation of the reaction. this makes some changes in the thermodynamics and kinetics of the reaction
catalyst speeds up the reaction... i don't know if there is actually 'a new route' in product formation because catalysts should not affect the reaction... it only has to speed up the reaction
a catalyst does not provide a new route. a catalyst effects the rate of a reaction by lowering the activation energy required for the reaction - the number of successful collisions and reactions therefore increase and rate of reaction increases.
A catalyst may provide a new route in forming a product. Often the reactants have too much energy and bounce off of each other forming few products. The catalyst may provide a surface where the reactants can settle momentarily in close proximity completing the reaction at an increased rate. The catalyst has been pictured (for illustration only) as a surface filled with grooves and when the reactants settle within the grooves (forming a film?) they are close enough to react rather than bounce off of each other. As such the catalyst facilitates the reaction without being used up in the reaction. The catalyst may become 'poisoned' with other molecules that interfere with the desired reaction and the reactants may have to be relatively pure to protect the catalyst.
A catalyst will almost always provide an alternative route for the reaction in question. It is common to hear the statement that a catalyst does not take part in a reaction, but that is almost always untrue. Properly defined, a catalyst is a species that alters the rate of a chemical reaction and which can be recovered unchanged BY MASS at the conclusion. In other words, the amount of catalyst present at the end of the reaction is the same as the amount at the start, but the catalyst itself has likely reacted many many times as the reaction proceeded. A simple example is the decomposition of hydrogen peroxide. The reaction taking place can be summarised as: 2 H2O2(l) ---2 H2O(l) + O2(g) This reaction is very slow under normal circumstances. However, if you drop in a crystal of potassium iodide, the reaction becomes extremely fast. The reason is that the potassium iodide dissolves and dissociates releasing iodide ions. These provide a new two-step reaction pathway in which both steps are rapid: H2O2 + I- ---H2O + IO- H2O2 + IO- ---H2O + O2 + I- Notice that if you add these equations together you get the same overall reaction as before. The iodide ion does not take part in the overall reaction, and so must be present at the end. However, it does take part in the mechanism of the reaction, and is undergoing a lot of reactions.
