Moderate

According to the law of mass action, "The rate of chemical reaction" is proportional to the:

Correct answer: B. Product of the molar concentration of reactants.

  • A. The amount of product formed.
  • B. Product of the molar concentration of reactants.
  • C. The initial concentration of reactants.
  • D. Catalyst.
  • E. Pressure.

Explanation

The speed at which the reactants are converted to products is called the rate of reaction. There are many factors that affect the speed of conversion of reactants into products: Nature of reaction: The state and number of reactants and complexity of reaction can affect the rate of reaction. Effect of concentration: From the law of mass action, the rate of reaction is directly proportional to the concentration of reactants, that is, the rate of reaction increases with the increase in the concentration of reactants. Pressure: The concentration of reactants can be increased by pressure. Hence, when pressure is increased the speed of reaction also increases. Catalyst: It can increase speed in both reverse and forward directions. This gives another path having low activation energy. Temperature: The reaction which takes place at a high temperature has more energy than a reaction at a low temperature. Now, we have to know what the law of mass action states which will give us a clearer answer to this question. Therefore, according to the law of mass action, "the rate of the chemical reaction is directly proportional to the product of the activities or concentrations of the reactants". So, from this statement, we can conclude that the rate of reaction depends upon the concentrations of the reactants which increase the speed of reaction with the increase in the chemical reaction. Hence the correct option is B.

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About Chemical Equilibrium

Reversible reactions reach dynamic equilibrium when forward and reverse rates become equal, and Le Chatelier's principle predicts the effect of changing concentration, pressure or temperature. The chapter also covers solubility product, the common ion effect, buffer action and the conditions used in Haber's process, with equilibrium shifts distinguished from changes in the equilibrium constant.

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