In this reaction 50% of the compound decompose in 10.5 min thus, it is half life of the reaction and denoted by symbol
.
(a) For first order reaction, rate constant and half life time are related to each other as follows:

Thus, rate constant of the reaction is
.
(b) Rate equation for first order reaction is as follows:
![k=\frac{2.303}{t_{1/2}}log\frac{[A_{0}]}{[A_{t}]}](https://tex.z-dn.net/?f=k%3D%5Cfrac%7B2.303%7D%7Bt_%7B1%2F2%7D%7Dlog%5Cfrac%7B%5BA_%7B0%7D%5D%7D%7B%5BA_%7Bt%7D%5D%7D)
now, 75% of the compound is decomposed, if initial concentration
is 100 then concentration at time t
will be 100-75=25.
Putting the values,

On rearranging,

Thus, time required for 75% decomposition is 21 min.
Sodium fluoride- to brush teeth
Citric acid- orange juice for breakfast
Sodium hydroxide- cleaning agent
Answer:
<em>the </em><em>two </em><em>elements</em><em> </em><em>are </em><em>in </em><em>the</em><em> same</em><em> </em><em>period</em><em>,</em><em> with</em><em> </em><em>element </em><em>R </em><em>the </em><em>first</em><em> </em><em>element</em><em> </em><em>in </em><em>the</em><em> </em><em>period</em><em> </em><em>and </em><em>element </em><em>Q </em><em>the </em><em>last</em><em> </em><em>element</em>
Answer:
The correct answer is - discovering or diagnosing the disease.
Explanation:
According to the question, this technology includes genetically modifying a common virus in order to destroy or kill the deadly brain tumor without affecting normal cells around the tumor, this technique is genetic engineering.
This technique can help in treating or curing the disease by killing the tumor cells and make them non-lethal. It can also prevent the tumor cells to grow and make them controlled. There is nothing mention related to diagnosing the disease in the question and it is not possible to find this tumor with help of such a technique.
Answer: The Sun Could Be Seen Once during the year when north of the equator.