Order of a Reaction - Characteristics of First Order Reaction

In a first-order reaction, 10% of the reactant is consumed in 25 minutes. Calculate:

(1) The half-life period of the reaction.

(2) The time required for completing 87.5% of the reaction.

Two moles of NH₃ are introduced into the one-litre flask in which it dissociates at high temperature as follows: 2NH₃(g)  ⇌ N₂(g) + 3H₂(g). Determine Kc, if at equilibrium 1 mole of NH₃ remains.

(i)

Write the mathematical expression relating to the variation of the rate constant of a reaction with temperature. 
(ii)

How can you graphically find the activation energy of the reaction from the above expression?
(iii)

The slope of the line in the graph of log k (k = rate constant) versus `1/"T"` is -5841. Calculate the activation energy of the reaction.

40% of a first-order reaction is completed in 50 minutes. How much time will it take for the completion of 80% of this reaction?

Fill in the blanks by choosing the appropriate word(s) from those given in the brackets:

(two, four, sec^-1, diamagnetic, acetaldehyde, mol^-1L sec^-1, paramagnetic, formaldehyde, acetone, ethanol)

When the concentration of a reactant of first-order reaction is doubled, the rate of reaction becomes ______ times. The unit of rate constant (k) for the first-order reaction is ______.