Conventional volcanoes are known to erupt after pressure builds up from new magma flowing into the magma chambers that lie below the vents on the Earth's surface.
Answer:


Explanation:
first write the equilibrium equaion ,
⇄ 
assuming degree of dissociation
=1/10;
and initial concentraion of
=c;
At equlibrium ;
concentration of
![[C_3H_5O_3^{-} ]= c\alpha](https://tex.z-dn.net/?f=%5BC_3H_5O_3%5E%7B-%7D%20%20%5D%3D%20c%5Calpha)
![[H^{+}] = c\alpha](https://tex.z-dn.net/?f=%5BH%5E%7B%2B%7D%5D%20%3D%20c%5Calpha)

is very small so
can be neglected
and equation is;

= 
![P_H =- log[H^{+} ]](https://tex.z-dn.net/?f=P_H%20%3D-%20log%5BH%5E%7B%2B%7D%20%5D)





composiion ;
![c=\frac{1}{\alpha} \times [H^{+}]](https://tex.z-dn.net/?f=c%3D%5Cfrac%7B1%7D%7B%5Calpha%7D%20%5Ctimes%20%5BH%5E%7B%2B%7D%5D)
![[H^{+}] =antilog(-P_H)](https://tex.z-dn.net/?f=%5BH%5E%7B%2B%7D%5D%20%3Dantilog%28-P_H%29)
![[H^{+} ] =0.0014](https://tex.z-dn.net/?f=%5BH%5E%7B%2B%7D%20%5D%20%3D0.0014)


The hours taken for concentration to decrease from 0 to 74 min. to 0.21 m is 91.7 hours.
<h3>What is the rate law of a reaction?</h3>
Rate law depicts the rate of a chemical reaction depend on the concentration of the reactant.
The given reaction is second order reaction
Thus, the hours taken for concentration to decrease from 0 to 74 min. to 0.21 m is 91.7 hours.
Learn more about rate law of a reaction
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Acceleration is when something is being moved forward or back, motion is just movement, friction is two or more things rubbing together, so the answer should be B. gravity