Why is ester hydrolysis slow iin the beginning but is fast after sometime ?

Why the reaction between nitric acid and copper is slow in the beginning but fast after some time?

When KMnO_4 is added to oxalic acid, the decolourisation is slow in the begining but becomes instantaneous after sometime because

A balloon when kept in the sun,burst after sometime . Why ?

Why do silver jewellery, tarnish black after sometime ?

In a pesudo first order hydrolysis of ester in water, the following results are obtained Calculate the averagte rate of reaction between the time inverval 30 to 60 s.

If we add some table salt to water taken in a glass tumbler and stir with a spoon, we find no salt after sometime. Does the level of water change ? If not, why not ?

The initial concentration of ethyl acetane is 0.85 mol L^(-1) . Following the acid catalysed hydrolysis the , concentrations of ester after 30 min and 60 min of the reaction are respectively 0.8 and 0.754 mol L^(-1) . Calculate the rate constant and pseudo rate constant.

What do you observe by cutting an apple after sometime ?Why