Question

Which of the following is the best way to speed up the reaction?
A. make an effort to concentrate the reactants as best as possible.
B. Add a catalyst
C. Cool the reaction down
D. Increase the pressure on the system

Answer 1

Hint: Different chemical reactions have different speed. Some are very rapid and some are very slow. This speed of reaction is termed as the rate of reaction. This is influenced by the frequency of collisions between the particles and the energy.

Complete step by step solution:
There are several examples for fast and slow rates of reactions. Iron rusting is a slow process, i.e. it has a low reaction rate. While combustion of wood is a fast process, i.e. it has a very high reaction rate. Similarly, nuclear explosion also has a very high reaction rate.
The factors affecting the reaction rates are:
a)Temperature
When temperature is increased, there is a tendency for the particles to collide more, thus needing more energy. So the rate will be increased. But when the reaction is cooled, collision between the particles will be less, thus the rate will be decreased.
b)Concentration
It is also similar to temperature.
c)Pressure
When pressure is increased, the particles come closer, thereby increasing frequency. Thus the rate is increased.
d)Surface area
When the particle size is small, the surface area is larger. Then the rate is higher.
e)Catalysts
They are substances which increase the speed of reaction. Most of the catalysts are either simply transition metals or their compounds.
E.g. iron, nickel, etc.
Thus we can say that adding catalysts is the best way to speed up the reaction.

Hence the correct option is B.

Note:
The observable changes to measure the rate of reaction are:
a)Volume of a gas liberated
b)Precipitation formation
c)Change in mass during the reaction
d)Pressure changes
e)Temperature changes
f)Color changes