Answer:
The correct answer is option 3.
Explanation:
2A → B + C
First trial ;
[A] = x , Rate of the reaction = R
Rate law of the reaction can be written as:
..[1]
Second trial ;
[A] = 3x , Rate of the reaction = R' = 9R
Rate law of the reaction can be written as:
![R'=k[3x]^a](https://tex.z-dn.net/?f=R%27%3Dk%5B3x%5D%5Ea)
..[2]
[1] ÷ [2]
![\frac{R}{9R}=\frac{k[x]^a}{k[3x]^a}](https://tex.z-dn.net/?f=%5Cfrac%7BR%7D%7B9R%7D%3D%5Cfrac%7Bk%5Bx%5D%5Ea%7D%7Bk%5B3x%5D%5Ea%7D)
a = 2
Rate of the reaction : ![R=k[A]^3](https://tex.z-dn.net/?f=R%3Dk%5BA%5D%5E3)
The order of the reaction is 2. This is because in the rate law expression the the power of the concentration of reactant A id 2.
It is a scientific theory because it is built on investigations by many scientists in order to provide a strong and testable explanation. A scientific theory is an in-depth explanation, whereas a scientific law is statement about an observed phenomenon or a unifying concept.
Answer. Statement second and third both are correct.
Explanation: When iron(grey) reacts with sulfur(yellow) chemical change takes place in which iron sulfide is formed which black in color.

When we heat copper sulfate-pentahydrate(blue) ,water molecule present in its crystal will get evaporated and it will become an anhydrous copper sulfate which will be white in color.

So, in both the reactions change in color and change in chemical arrangement has taken place.
The center of a plant cell is a nucleus!
Answer:
The International System of Units (SI) is originated in France by frenches and originally was called a metric system of measurements. It provides definitions of various units of measurement such as weight, distance, electric current, temperature, and others which is widely accepted in the different fields of science and technology.
It is the system that is extended and derived from the french metric system of measurement is accepted in 1960 by convention 44 nation of the world to use particular unit of measurement worldwide to avoid confusion.