Read the passage given below and answer the questions that follow : Some reactions such as ionic reactions occur very fast, for example, precipitation of silver chloride occurs instantaneously by mixing of aqueous solutions of silver nitrate and sodium chloride. On the other hand, some reactions are very slow, for example, rusting of itin in the presence of air and moisture. Also there are reactions like inversion of care matter and hydrolysis of starch, which proceed with a moderate speed. Can you think of mere examples from each category ?You must be knowing that speed of an automobile is expressed in ferms of change in the position or distance covered by it in a certain period of time. Similarly. the speed of a reaction or the rate of a reaction can be defined as the change in concentration of a reactrant or product in unit time. To be more specific, it can be expressed in terms of (i) the rate of decrease in concentration of any one of the reactants, or (ii) the rate of increase in concentration of any one of the products. Q-1 Give two examples of very fast reactions other than the one given in the paragraph.Q-2 Give two examples of very slow reactions other than the one given in the paragraph.Q-3 How do we derive the equation for instantaneous rate?Q-4 How do we express the rate of reactions where stoichiometric coefficients of reactants or products are not equal to 1 ?                                       Or In the reaction of hydrolysis of butyl chloride represented by \[ C _{4} H _{4} Cl + H _{2} O \longrightarrow C _{4} H _{9} OH + HCl \text {, } \] the concentration of butyl chloride at time \( 50 s \) and \( 100 s \) are \( 0.0505 \) and \( 0.5820 \) mol \( L ^{-1} \) respectively. Calculate the average velocity for this interval.