Suppose you place an ice cube into a cup of hot tea? What will happen to the temperature of the ice cube and the tea? A) The tem
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Answer : A= 0.5, B = 0.25 , C = 0.125, D = 0.015625 and E = 0.00390625
Explanation :
Half life of a substance is defined as the amount of time taken by the substance to reduce to half of its original amount.
Here n represents the number of half lives.
The amount of substance that remains after n half lives can be calculated using the given formula,
So when we have n =1,
Fraction of substance that remains = 0.5¹ = 0.5.
That means after first half life over, the amount of substance that remains is 0.5 times that of original.
Therefore we have A = 0.5
When n = 2, we have 0.5² = 0.25
So when 2 half lives are over, the amount of substance that remains is 0.25 times that of original
Therefore B = 0.25
When n = 3, we have 0.5³ = 0.125
So when 3 half lives are over, the amount of substance that remains is 0.125 times that of original.
Therefore we have C = 0.125
When n = 6 , we have 0.5⁶ = 0.015625
So D = 0.015625
When n = 8, we have 0.5⁸ = 0.00390625
Therefore E = 0.00390625
The values for A, B, C, D and E are 0.5, 0.25, 0.125, 0.015625 and 0.00390625 respectively.
Ethyl Butanoate when treated with a base looses a proton which is more acidic in nature. In this case ethyl butanoate acts as a lowery bronsted acid. It donated the more acidic proton to lowery bronsted base.
Among the protons attached to different carbon atoms the hydrogen atoms next to carbonyl functional group (labelled as red in attached picture) are more acidic in nature and are readily donated on treatment with strong base. These hydrogen atoms are also called alpha hydrogen name after their position.
Acidity of Alpha Hydrogens:
The driving force behind the acidity of alpha hydrogens is the formation of enolates. The enolate formed is resonance stabilized. This stability is the main reason for the said acidity. The pKa value of said protons is approximately 20-25. Hence, the enolate formed is infact the conjugate base and can act as neucleophile.
