Question

in a zero order reaction the time taken to reduce the concentration of the reactants from 50% to 25% is 30 minutes. what is the time required to reduce the concentration from 25 % to 12.5%

Answer 1

Dear student,

● Answer -
Time required = 15 min

● Explaination -
Let X be the initial conc. of reactants.

For any zero order reaction, rate is constant throughout the reaction not varied by change in reactant conc.


Rate of reaction is calculated by -
R = (50-25)% X / 30
R = (25/100)X / 30
R = X / 120 .

Time required for reactants to decrease from 25% to 12.5% is given by -
R = (25-12.5)% X / t
X / 120 = X / 8t
t = 15 min.

Therefore, 15 min will be required to reduce concentration from 25% to 12.5%.

Answer 2

Answer:

I'll try to say n give u the easy way for this type of question;

Now they given that the initial concentration i.e., [A•] is 50% and then it becomes 25% i.e., our [A] and time is 30 mins

Now we all know the formula for zero order reaction that is;

t = [A•]-[A]/k

Now substitute the values

30mins = 50-25/k i.e.,

30mins = 25/k ----------->1

And then they gave that initial concentration i.e., [A•] us 25% and [A] is 12.5% and t we have to find

Now again;

t = [A•]-[A]/k

Now substitute the values

t = 25-12.5/k

t = 12.5/k ----------->2

Now divide equation 2 by 1 i.e.,

t / 30mins = 12.5/k /25/k

K na k will get cancelled

Now t / 30mins = 12.5/25

t / 30 mins = 0.5

t = 0.5*30mins

t = 15mins

Waoh got it I guess

I hope u understood guys thank u

Explanation: