Astronauts are found wearing orange-colored Advanced Crew Escape Suit (ACES) while the space shuttle is ascending or entering into space. This peculiar shade of orange known as “International Orange” was chosen for safety as it is highly visible against any kind of landscape, especially in the sea.
Answer : The value of Ka for acetic acid is, 
Explanation :
The chemical formula of acetic acid is,
.
The chemical equilibrium reaction will be:

Given:
pH = 2.96
First we have to calculate the concentration of hydrogen ion.
![pH=-\log [H^+]](https://tex.z-dn.net/?f=pH%3D-%5Clog%20%5BH%5E%2B%5D)
![2.96=-\log [H^+]](https://tex.z-dn.net/?f=2.96%3D-%5Clog%20%5BH%5E%2B%5D)
![[H^+]=1.096\times 10^{-3}M](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%3D1.096%5Ctimes%2010%5E%7B-3%7DM)
That means,
![[H^+]=[CH_3COO^-]=1.096\times 10^{-3}M](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%3D%5BCH_3COO%5E-%5D%3D1.096%5Ctimes%2010%5E%7B-3%7DM)
![[CH_3COOH]=0.0602-(1.096\times 10^{-3})=0.0591M](https://tex.z-dn.net/?f=%5BCH_3COOH%5D%3D0.0602-%281.096%5Ctimes%2010%5E%7B-3%7D%29%3D0.0591M)
The expression for reaction is:
![K_a=\frac{[CH_3COO^-][H^+]}{[CH_3COOH]}](https://tex.z-dn.net/?f=K_a%3D%5Cfrac%7B%5BCH_3COO%5E-%5D%5BH%5E%2B%5D%7D%7B%5BCH_3COOH%5D%7D)


Thus, the value of Ka for acetic acid is, 
The third option is the answer
Weathering is the process that changes solid rock into sediments. Sediments were described in the Rocks chapter. With weathering, rock is disintegrated. It breaks into pieces.
To covert from moles to atoms times the number of moles by Avogadro's Number (6.022×10²³)
4.0 × 6.022×10²³ = 2.4088×10^24